Subtype Of Large B-cell Lymphoma Research Articles

Primary Mediastinal Large B-cell Lymphoma – A Case Report

AbstractPrimary mediastinal large B-cell lymphoma (PMBL) is an uncommon and aggressive subtype of non-Hodgkin large B-cell lymphoma that affects patients in the third and fourth decades of life. The objective of the present report is to describe the case of a male patient admitted to the emergency room with symptoms of dyspnea associated with signs of superior vena cava syndrome. The imaging exams revealed two masses in the mediastinum; the definitive diagnosis, established through an anatomopathological examination and immunohistochemistry, was of PMBL, and the patient was referred for chemotherapy.

Lymphoma cell-driven IL-16 is expressed in activated B-cell-like diffuse large Bcell lymphomas and regulates the pro-tumor microenvironment.

The activated B-cell-like subtype of diffuse large B-cell lymphoma (ABC-DLBCL) displays a worse outcome than the germinal center B-cell-like subtype (GCB-DLBCL). Currently, targeting tumor microenvironment (TME) is the promising approach to cure DLBCL with profound molecular heterogeneity, however, the factors affecting the tumor-promoting TME of ABCDLBCL are elusive. Here, cytokine interleukin-16 (IL-16) is expressed in tumor cells of ABCDLBCL and secreted by the cleavage of active caspase-3. The serum IL-16 levels are not only a sensitive marker of treatment response but also positively correlated with unfavorable prognosis in DLBCL patients. While IL-16 shows few direct promotional effects on tumor cell growth in vitro, its bioactive form significantly promotes tumor progression in vivo. Mechanically, IL-16 increases the infiltration of macrophages by the chemotaxis of CD4+ monocytes in the TME enhancing angiogenesis, and the expression of cytokine IL-6 and IL-10, as well as decreasing T cell infiltration to accelerate tumor progression. This study demonstrates that IL-16 exerts a novel role in coordinating the bidirectional interactions between tumor progression and the TME. IMM0306, a fusion protein of CD20 mAb with the CD47 binding domain of SIRPα, reverses the tumorpromoting effects of IL-16,which provides new insight into treatment strategy in ABC-DLBCL.

TCP1 expression alters the ferroptosis sensitivity of diffuse large B-cell lymphoma subtypes by stabilising ACSL4 and influences patient prognosis

Diffuse large B-cell lymphoma (DLBCL), an invasive lymphoma with substantial heterogeneity, can be mainly categorised into germinal centre B-cell-like (GCB) and non-GCB subtypes. DLBCL cells are highly susceptible to ferroptosis, which offers an effective avenue for treating recurrent and refractory DLBCL. Moreover, various heat shock proteins are involved in regulating the sensitivity of tumour cells to ferroptosis. Among these proteins, tailless complex polypeptide 1 (TCP1), a subunit of chaperonin-containing T-complex protein-1 (CCT), plays a role in tumour proliferation and survival. Therefore, we explored the role of TCP1 in different DLBCL subtypes, the sensitivity of GCB and non-GCB subtypes to the ferroptosis inducer RAS-selective lethal small molecule 3 (RSL3), and the underlying molecular mechanism. In GCB cells, TCP1 promoted RSL3-induced ferroptosis. Notably, TCP1 could bind with acyl-CoA synthetase long-chain family member 4 (ACSL4), a key enzyme regulating lipid composition and facilitating ferroptosis, to reduce its ubiquitination and degradation. This interaction activated the ACSL4/LPCAT3 signalling pathway and promoted ferroptosis in the GCB subtype. However, in the non-GCB subtype, TCP1 did not act as a positive regulator but served as a predictor of an unfavourable prognosis in patients with non-GCB. In conclusion, our results suggest that in DLBCL, high TCP1 expression enhances the sensitivity of GCB tumour cells to ferroptosis and serves as a marker of poor prognosis in patients with non-GCB DLBCL.

Characteristics and outcomes of plasmablastic lymphoma in a predominantly Hispanic population.

e19079 Background: Plasmablastic lymphoma (PBL) is a rare subtype of diffuse large B-cell lymphoma and is frequently associated with immunosuppression. PBL displays immunoblastic morphology and a plasma cell immunophenotype. Data regarding patient characteristics, outcomes, and optimal treatment for this disease is limited. The reported prognosis of patients with PBL has been historically poor, with median overall survival ranging from 6 to 18 months. A recent publication of the SEER/NCDB database found a significantly improved OS in the Hispanic population (HR 0.7, p=0.014). This study investigates demographic, treatment, and survival outcomes for a primarily Hispanic PBL population. Methods: We identified 42 cases of pathologically confirmed PBL at two high volume tertiary care centers in Southern California between March 2010 and June 2023. Chart review was used to collect data on clinical presentation, treatment, and outcomes. Results: Median age of patients at diagnosis was 46 years (range 17-91 years) and 90% were male. Hispanic patients represented 81% of the total cohort. Predisposing immunosuppression was identified in 60%, and 50% of the total cohort were HIV-positive. Pathologic analysis showed EBV positivity by EBER in situ hybridization in 67%. 76% of patients presented with advanced disease (Stage III/IV). The most common regimens were EPOCH (27%) and V-EPOCH (49%). Response rates and CR rates were 63% and 50% respectively. Median follow-up was 10.5 months. OS was 72% at 1-year and 60% at 2-years. Conclusions: Our cohort demonstrated a 1-year OS of 72% compared to the 56% 1-year OS for PBLs in the SEER/NCDB database. There was no statistically significant difference in survival between the Hispanic and Non-Hispanic cohorts in our study. However, this is likely due to the small sample size in the latter. Notably, our patient population had more advanced disease at presentation (76% Stage III/IV) than the SEER/NCDB cohort (60% Stage III/IV). This improved survival is likely multifactorial, but could represent ethnic differences in PBL biology, high EBV positivity, and the frequent utilization of higher intensity regimens (EPOCH/V-EPOCH = 76%). Further studies are needed to better characterize this disease in the Hispanic population. [Table: see text]

Cerebellum/liver index on baseline 18F-FDG PET/CT to improve prognostication in post-transplant lymphoproliferative disorders: a multicenter retrospective study

BackgroundBesides International Prognostic Index (IPI) score, baseline prognostic factors of post-transplant lymphoproliferative disorders (PTLD) are poorly identified due to the rarity of the disease. New indexes derived from healthy organ uptake in baseline 18F-FDG PET/CT have been studied in immunocompetent lymphoma patients. The aim of this study is to evaluate the performances of the cerebellum-to-liver uptake ratio (denoted as CLIP) as a prognostic factor for PFS and OS. This retrospective multicenter study is based on patients with PTLD included in the K-VIROGREF cohort. The previously published threshold of 3.24 was used for CLIP in these analyses.ResultsA total of 97 patients was included with a majority of monomorphic diffuse large B-cell lymphoma subtype (78.3%). Both IPI score (≥ 3) and CLIP (< 3.24) were significant risk factors of PFS with corresponding hazard ratios of 2.0 (1.0–4.0) and 2.4 (1.3–4.5) respectively. For OS, CLIP was not significant and resulted in a hazard ratio of 2.6 (p = 0.059). Neither IPI score or Total Metabolic Tumor Volume reached significance for OS.ConclusionCLIP is a promising predictor of PFS and perhaps OS in PTLD. Further prospective studies are needed to confirm these results.

Abstract 2265: Distinct alternative splicing patterns in genetic subtypes of diffuse large B-cell lymphoma

Abstract Advances in sequencing techniques have made molecular subgrouping of Diffuse Large B-cell Lymphoma (DLBCL) based on DNA cahnges, which has led to the development of Lymphgen classification. By the way, although alternative splicing (AS) in cancer cells contributes to proliferation, invasion and metastasis, and immune escape, their role and association with DLBCL molecular subtypes are unknown. Therefore, we analyzed whole-exome sequencing (WES) and bulk RNA-Seq data paired in the public EGA dataset (EGAD00001003600) to explore the patterns of AS events that differ between Lymphgene subtypes. The WES data of 620 DLBCL samples that passed quality control were aligned to the reference using BWA-MEM, and variants were called with Mutect2. We used the information of copy number variants provided by cBioPortal. The RNA-Seq analysis was performed using the STAR-RSEM pipeline and differential splicing events were detected using rMATS to compare subtypes. Among 620 DLBCL samples, there were 19 MCDs, 95 EZBs, 22 BN2s, and 137 ST2s (50 samples with multiple genetic classes, and 291 samples unclassified). Mutations in spliceosome complex genes (ZRSR2 and SF1) were found in 14 and 27 samples, respectively. In BN2 and MCD subtypes, splicing events with significantly different exon inclusion levels were observed at a high frequency of 29 and 16 occurrences, respectively, compared to other subtypes. (P-value &amp;lt; 0.05). In contrast, retained intron is the only event observed in the EZB subtype (Table 1). Samples with mutations in ZRSR2 and SF1 showed four and two aberrant events, respectively, compared to samples without these mutations. Of note, rMATS detected an alternative 3’ splice site event in exon 6 of CD37 in the MCD. CD37 is involved in tumorigenesis in leukocytes and has been suggested as a potential biomarker in blood cancer, and its dysregulation may have influenced the poor prognosis of MCD. In summary, molecular subtypes of DLBCL had unique features in terms of alternative splicing. Functional consequences of these selective exon usages for each DLBCL subtype are being warranted. Citation Format: Sanyeowool An, Youngil Koh, Sung-Soo Yoon. Distinct alternative splicing patterns in genetic subtypes of diffuse large B-cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2265.

Abstract 6549: Mechanistic models of tumor and patient heterogeneity explain and predict clinical outcomes of large B-cell lymphoma (LBCL) treatment

Abstract Introduction: Heterogeneity between patients and within tumors poses challenges to effective cancer treatment. Drug combinations can overcome heterogeneity by increasing the probability that a patient will have response to one or more drugs. This approach is successful in numerous disease settings, but technological advances have led to new approach to addressing heterogeneity: precision approaches to stratify patients into subpopulations with more uniform, stronger responses to specific drugs. These strategies can be implemented together to improve patient outcomes. We have developed computational mechanistic models of cancer treatment in the context of both sources of heterogeneity which explain and predict clinical outcomes of treatment of LBCL with combination therapy and CAR T-cell therapy. Combination therapy: Our novel population tumor kinetics (pop-TK) model simulates clinical combination therapy outcomes by implementing multidrug dose response functions in heterogeneous populations of tumor cells, within heterogeneous cohorts of patients. Informed by the outcomes of novel drugs in phase 2 trials in relapsed/refractory (r/r) patients, the pop-TK model accurately predicted of outcomes of seven first-line phase 3 trials of novel combinations. Most notably, informed by treatment of r/r LBCL with polatuzumab-vedotin (pola), the pop-TK predicted the success of modifying the standard treatment regimen (RCHOP) with pola before the clinical trial results were published. The pola combination improves overall survival (OS) and PFS in Activated B-Cell (ABC) LBCL (hazard ratio (HR): OS 0.3, PFS 0.4), but reduces OS (HR: 1.6) and does not improve PFS (HR: 1.0) in Germinal Center B-Cell (GCB) LBCL. The subtype specific difference in PFS was also predictable based on subtype results of r/r trials (predicted HR: ABC 0.3, GCB 0.9). CAR T-cell therapy: We used a population pharmacokinetic/pharmacodynamic (pop-PK/PD) model of CAR T-cell therapy to reproduce the PFS distribution and the distribution CAR T-cell abundance for CAR T therapy in r/r LBCL patients. The impact of tumor size on patient outcome in our model and in clinical studies led us to computationally explore the impact treating smaller tumors with CAR T-cell therapy on treatment outcomes. We found that using detectable circulating tumor DNA (ctDNA) as a biomarker for administering CAR T-cell therapy immediately after RCHOP increased the proportion of simulated patients without a second disease progression event by 30% (HR: 0.43 [0.34, 0.55]). Conclusions: The pop-TK model supports LBCL subtype biomarker for pola performance, and the pop-PK/PD model demonstrates that detectable ctDNA is a potential biomarker for early CAR T-cell administration. These examples of model-driven precision trial design have the potential to improve outcomes using readily-available biomarkers and existing therapies. Citation Format: Amy E. Pomeroy, Adam C. Palmer. Mechanistic models of tumor and patient heterogeneity explain and predict clinical outcomes of large B-cell lymphoma (LBCL) treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6549.

A Case of Plasmablastic Lymphoma Complicated with Pure Red Cell Aplasia Caused by T-cell Large Granular Lymphocytic Leukemia.

Plasmablastic lymphoma (PBL) is an aggressive subtype of large B-cell lymphoma associated with immunodeficient states, such as HIV and EBV infections, and aging. PBL frequently harbor STAT3 mutations, which are crucial for their development. We herein report a rare case of PBL complicated by T-cell large granular lymphocytic leukemia (T-LGLL) and pure red cell aplasia (PRCA). The patient was treated with six cycles of chemotherapy and developed transfusion-dependent anemia. Large granular lymphocytes and T-cell receptor rearrangement were detected, thus leading to the diagnosis of T-LGLL and PRCA. This is the first documented case of PBL with T-LGLL and PRCA, offering insight into PBL's pathophysiology and the complications of PBL.

Clinico-pathologic Profile of Filipino Patients Diagnosed with Diffuse Large B-Cell Lymphoma, Germinal Center or Non-germinal Center Subtype Treated in a Public Tertiary Hospital from 2016 to 2021

Clinico-pathologic Profile of Filipino Patients Diagnosed with Diffuse Large B-Cell Lymphoma, Germinal Center or Non-germinal Center Subtype Treated in a Public Tertiary Hospital from 2016 to 2021

CD5 Gene Signature Identifies Diffuse Large B-Cell Lymphomas Sensitive to Bruton's Tyrosine Kinase Inhibition.

A genetic classifier termed LymphGen accurately identifies diffuse large B-cell lymphoma (DLBCL) subtypes vulnerable to Bruton's tyrosine kinase inhibitors (BTKis), but is challenging to implement in the clinic and fails to capture all DLBCLs that benefit from BTKi-based therapy. Here, we developed a novel CD5 gene expression signature as a biomarker of response to BTKi-based therapy in DLBCL. CD5 immunohistochemistry (IHC) was performed on 404 DLBCLs to identify CD5 IHC+ and CD5 IHC- cases, which were subsequently characterized at the molecular level through mutational and transcriptional analyses. A 60-gene CD5 gene expression signature (CD5sig) was constructed using genes differentially expressed between CD5 IHC+ and CD5 IHC- non-germinal center B-cell-like (non-GCB DLBCL) DLBCLs. This CD5sig was applied to external DLBCL data sets, including pretreatment biopsies from patients enrolled in the PHOENIX study (n = 584) to define the extent to which the CD5sig could identify non-GCB DLBCLs that benefited from the addition of ibrutinib to rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). CD5 expression was observed in 12% of non-GCB DLBCLs. CD5+ DLBCLs displayed transcriptional features of B-cell receptor (BCR) activation and were enriched for BCR-activating mutations known to correlate with BTKi sensitivity. However, most CD5+ DLBCLs lacked canonical BCR-activating mutations or were LymphGen-unclassifiable (LymphGen-Other). The CD5sig recapitulated these findings in multiple independent data sets, indicating its utility in identifying DLBCLs with genetic and nongenetic bases for BCR dependence. Supporting this notion, CD5sig+ DLBCLs derived a selective survival advantage from the addition of ibrutinib to R-CHOP in the PHOENIX study, independent of LymphGen classification. CD5sig is a useful biomarker to identify DLBCLs vulnerable to BTKi-based therapies and complements current biomarker approaches by identifying DLBCLs with genetic and nongenetic bases for BTKi sensitivity.

B-Cell Maturation Antigen (BCMA) Expression and Clinical Features of Plasmablastic Lymphoma (PBL)

Introduction: Plasmablastic lymphoma (PBL) is a rare and aggressive subtype of large B-cell lymphoma with plasmacytic differentiation. Although limited-stage (LS) PBL has a favorable outcome, extensive-stage (ES) PBL has a poor prognosis, with a median survival of 12-18 months. Patients with relapsed/refractory (r/r) PBL have limited treatment options and most die from the disease. B cell maturation antigen (BCMA) - directed cellular and immunotherapies are highly effective in MM. The data on BCMA expression in PBL is limited. Literature review identified one report including 7 PBL cases all of which expressed BCMA. We studied all patients with a diagnosis of PBL who presented to Moffitt Cancer Center in Florida, USA from Jan. 2006 to Apr. 2023, and retrospectively performed BCMA immunohistochemistry (IHC) staining on the available archived FFPE biopsy samples. Methods: Progression-free survival (PFS) was calculated as time from disease progression or last follow up to treatment start date. Overall survival (OS) was calculated as time from death or last follow up to date of PBL diagnosis. Association of BCMA expression with PFS or OS was evaluated using logrank test, with continuous variables converted to categorical by classifying as above or below median. All analyses were done using SAS 9.2. Results: A total of 32 PBL patients were identified. The median age was 59 years (range 31-83 years); 21 (65.6%) had stage III/IV (ES); 9 patients (28.1%) were HIV positive; and 57.1% of evaluated cases were EBV positive by EBER. Treatment data was available for 30 patients. The most common frontline therapies were EPOCH and CHOP with or without rituximab; four patients received bortezomib combined with EPOCH; 7 patients (23.3%) received autoSCT in 1 st remission (Table 1). Median follow-up was 77.6 months calculated using the reverse Kaplan-Meier method. Consistent with previous reports, patients with ES PBL had worse outcome than those with LS PBL, with 3-year OS rates of 24% and 100%, respectively, p=0.01 (Table 1). Among the 20 patients with ES PBL and known treatment responses, 11 did not achieve CR after frontline therapy. Ten of these 11 patients died due to disease progression, 9 within 2 years and 1 within 3 years. Two patients received CD19 CAR-T after multiple lines of therapy. Both died within 30 days, one from disease progression and the other from multiple treatment complications. Out of the 18 cases with tissue available for IHC study, 17 (94.4%) had positive BCMA expression (Figure 1). The median percentage of BCMA+ cells was 75% (Table 1). Eleven (61.1%) cases had intermediate to strong BCMA staining. Neither BCMA+ cell percentage nor BCMA expression level was associated with disease stage, response rate, PFS, or OS (p&amp;gt;0.10 for all tests). Discussion: In our study the majority of our PBL cases tested positive for BCMA, and the percentage of BCMA+ cells seemed comparable to MM cases.To our knowledge, this is the largest and the first report that systemically evaluated BCMA expression in PBL. Our results provide evidence to explore BCMA as a potential target in PBL. Currently two anti-BCMA CAR-T products and an anti-BCMA/CD3 bispecific T-cell engager have been approved for r/r MM. A BCMA-targeting antibody-drug conjugate (ADC) Belantamab mafodotin-blmf was initially granted accelerated approval by FDA for r/r MM but was later voluntarily withdrawn from the market. Given the expression of BCMA in PBL and the lack of effective treatment of r/r PBL, these patients could be considered in trials evaluating the BCMA-targeting therapies. In fact, in a case report recently published, one patient with refractory PBL achieved CR after one infusion of BCMA CAR-T and remained in CR after 14 months. Ten of our 11 ES patients who did not achieve CR after frontline chemotherapy died from the disease, emphasizing the importance of clinical trials for this condition. We did not find an association of BCMA expression with clinical outcomes as oppose of MM, in which higher BCMA expression was associated with shorter PFS and OS. The lack of association in our study may be due to the small sample size, or, it may reflect a difference in biological role of BCMA in PBL from MM. Our results will need to be corroborated with other series to confirm our findings. Translational studies need to evaluate the dynamics of BCMA protein expression on PBL cell membrane and the activity of BCMA-targeting agents in vitro and in animal models of PBL.

Addition of High-Dose Methotrexate to Initial Chemotherapy Improved Treatment Outcome of Patients with Newly Diagnosed Intravascular Large B-Cell Lymphoma: A Multicenter, Retrospective Study

[Introduction] Intravascular large B-cell lymphoma (IVLBCL) is a rare subtype of diffuse large B-cell lymphoma characterized by selective growth of lymphoma cells in the lumina of small vessels. Although the clinical outcomes of IVLBCL before rituximab era were dismal, a retrospective analysis published in 2008 showed improved outcomes for patients treated with rituximab-containing chemotherapy (R-chemo). Furthermore, a recent multicenter, single-arm, phase II trial conducted in Japan (PRIMEUR-IVL study) supports the usage of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone combined with high-dose methotrexate (HD-MTX) and intrathecal chemotherapy (IT), with a 2-year Overall survival (OS) of 92% and 2-year progression-free survival (PFS) of 76% in a selected population with newly diagnosed IVLBCL. However, this trial did not include a control arm, making it difficult to evaluate whether the addition of HD-MTX improves the treatment outcome. Thus, with the largest cohort (we already reported at ASH 2022), we retrospectively evaluated the efficacy of the HD-MTX in real-world settings. [Methods] Patients with histopathologically proven newly diagnosed IVLBCL according to the 2008 World Health Organization criteria between January 2010 through February 2022 from hospitals participating in the North Japan Hematology Study Group were included. Survival analysis was limited to patients with serum creatinine &amp;lt; 2.0 mg/dL and aged 20-79 years, following the eligibility criteria of the PRIMEUR-IVL study. PFS was defined as the time from the start of treatment to the first of progression, relapse, or death from any cause. Patients undergoing upfront autologous stem-cell transplantation (auto-SCT) were censored at the time of transplantation. [Results] A total of 110 IVLBCL cases were identified. Eighty-six patients with serum creatinine &amp;lt; 2.0 mg/dL, aged 20-79 years, received chemotherapy. Eighty-five of 86 patients (98.8%) received R-chemo. Thirty-six of 86 patients (41.9%) received HD-MTX during the initial therapy (w HD-MTX group), and 50 patients (58.1%) did not (w/o HD-MTX group). Fifty-six patients (65.1%) received IT. Six patients (7.0%) received upfront auto-SCT. Complete response (CR), no change (NC), and primary refractory disease were noted after initial therapy by 62 (72.1%), 11 (12.8%), and 11 (12.8%) patients, respectively. The disease progression after achieving NC was noted in 3 patients (3.5%). Fourteen patients (16.3%) experienced a relapse after achieving CR. Eight of 28 recurrences (progressions or relapses) were neurolymphomatosis forms, and 7 were central nervous system (CNS) recurrences. Twenty-five patients (29.1%) died, and 21 were due to disease progression. Compared clinical characteristics of the w HD-MTX group with the w/o HD-MTX group, the proportion of patients older than 60 years, male sex, poor performance status (ECOG PS &amp;gt; 1), elevated serum LDH, Ann Arbor stage III-IV and 2 or more extra-nodal lesions were not significantly different. The number of patients who received IT was significantly higher in the w HD-MTX group (77.8% vs. 56.0%, P = 0.042). Median follow-up duration for censored cases was 47.1 months (range, 7.4-130.7 months) in w HD-MTX group and 33.0 months (range, 1.78-140.5 months) in w/o HD-MTX group. Two-year PFS and OS were 73.1% (95% CI, 54.5-85.0) and 85.0% (95% CI, 67.5-93.5), respectively, in the w HD-MTX group and 54.7% (95% CI, 38.6-68.3) and 69.2% (95% CI, 53.2-80.6), respectively, in the w/o HD-MTX group (log-rank test, P = 0.016 and P = 0.005, respectively; Fig. a, b). The w HD-MTX group and the w/o HD-MTX group showed no significant difference in the cumulative incidence of CNS recurrence at 2 years (8.7%; 95% CI, 2.2-21.0 vs. 6.6%; 95% CI, 1.7-16.5, Gray test, P = 0.98). In univariate analysis, male gender, the addition of IT, and the addition of HD-MTX were significantly associated with PFS and OS ( Table). Multivariate analysis demonstrated that the addition of HD-MTX was independently associated with both PFS and OS. No HD-MTX-related deaths occurred in the w HD-MTX group. Adverse events related to HD-MTX were observed in 24 of 36 patients (66.7%), with grade 3 or 4 non-hematological adverse events in 3 patients (8.3%). [Conclusion] In conclusion, this largest retrospective study showed that the addition of HD-MTX to initial chemotherapy improved the treatment outcome of patients with newly diagnosed IVLBCL.

Skeletal Muscle Index, As a Measure of Muscle Mass, Is a Significant Prognostic Factor for Newly Diagnosed Diffuse Large B-Cell Primary CNS Lymphoma Patients

Background: Primary cerebral lymphoma (PCNSL) is a rare subtype of diffuse large B-cell lymphoma (DLBCL) with a particularly poor outcome compared to systemic DLBCL. Several prognostic scores have been developed for PCNSL. These include the International Extranodal Lymphoma Study Group (IELSG) score with five prognostic factors (patient age, serum lactate dehydrogenase [LDH] level, Eastern Cooperative Oncology Group performance status [PS], deep brain involvement and cerebrospinal fluid [CSF] protein level), and the Memorial Sloan-Kettering Cancer Center (MSKCC) score, which is based on age and the Karnofsky Performance Score (KPS). However, the reproducibility of these two scoring systems is low, and the IESLG score requires CSF protein and LDH levels evaluation, which are not often available. None of these scores incorporate data on nutritional status, in particular albumin, which has been shown to be an important prognostic factor in systemic DLBCL. In addition, a recent study demonstrated that the muscle density and mass determined by imaging segmentation, were strong prognostic factors for newly diagnosed systemic DLBCL patients (Jullien et al. Cancers 2021). Our aim was to determine whether these imaging data were also predictive factors for outcome in newly diagnosed diffuse large B-cell PCNSL patients. Methods: For each patient included in the study, muscle mass and density were estimated using skeletal muscle index (SMI) and mean skeletal muscle radiation attenuation (SMRA), respectively. SMI and SMRA were computed at L3 level using the whole-body scan (WBS) performed at the diagnosis of PCNSL, by the mean of an automated segmenting algorithm. Muscle characteristics were then classified as normal or low using already validated cut-off according to patients' age and body mass index (Westenberg et al. Sci Rep 2023). Patients' outcomes were then compared based on their muscle quality, albumin level at diagnosis and other clinical variables commonly included in PCNSL prognostic scores. Results: Between 2015 and 2022, 98 consecutive diffuse large B-cell PCNSL patients were newly diagnosed at Hematology Department of Hospital Lyon Sud, France. Among them, 77 had WBS at diagnosis with available data for this study. The median age was 69 years (range 24-87) and 22 patients (29%) presented an altered ECOG PS (PS 3-4 score). All patients were treated with first-line high-dose methotrexate-based chemotherapy in combination with rituximab. SMI was normal in 64 patients (83%) and 17 patients (17%) had low SMI. Patients with low SMI had more frequently an altered PS (p=0.07) and had lower albumin level (mean 36.7 g/L vs 32.0 g/L, p=0.007). SMRA was normal in 30 patients (39%) and 47 patients (61%) had low SMRA. Patients with low SMRA were older (60 vs 70 years old, p=0.001). In univariate analysis, patients with low SMI had worse outcome with significantly shorter overall survival (p=0.002, median OS, 21.4 months vs not reached) and a trend towards shorter event-free survival (p=0.055, median EFS, 11.9 months vs 42.3 months, Figure 1). No significant prognostic difference was seen for SMRA for EFS or OS. The multivariate analysis showed that SMI (Hazard ratio [HR]=3.33, 95% confidence interval [95%CI]= 1.21-9.20, p=0.02) and age (HR =1.86, 95%CI =1.15-3.0, p=0.012) were strongly associated with OS but not tumor localization (HR =1.46, 95%CI =0.60-3.55, p=0.4), PS (HR = 1.54, 95%CI =0.65-3.65, p=0.32) and albumin level (HR =1.05, 95%CI =0.47-2.32, p=0.91). Age was significantly associated with EFS (HR=1.4, p = 0.04) with a more limited association of SMI with EFS (HR=2.03, p=0.095). In exploratory subgroup analyses, we showed that SMI still influenced OS in patients with PS 4 (10 months vs not reached, p= 0.002), suggesting that SMI may be a more appropriate prognostic factor than PS, especially for patients with motor deficit for whom PS is difficult to estimate. Conclusions: This retrospective analysis of newly diagnosed PCNSL patients showed a significant association between decreased muscle mass, measured by SMI and overall survival, after controlling for other prognostic variables. These findings warrant confirmative analyses to explore the relationship between muscle mass/density and diffuse large B-cell PCNSL patient's outcome and integrate SMI in PCNSL prognostic scores.

Autologous Stem Cell Transplantation Remains a Curative Option As Second Line Treatment for Patients with Relapsed/Refractory Large B Cell Lymphoma: Spanish Multicenter Geth-TC/Geltamo Study

Introduction: High dose therapy and Autologous Stem Cell Transplantation (ASCT) has remained the treatment of choice for transplant-eligible patients with relapsed/refractory (R/R) large B cell lymphoma (LBCL) and chemosensitive disease. Recently, CART therapy has been approved in second line for patients with primary refractory disease or early relapse (&amp;lt;1 year of first-line therapy) and the current role of ASCT has been questioned. However, several studies have shown that despite early failure of first line, patients with chemosensitive disease after salvage therapy can be cured with ASCT consolidation. Our objective was to analyze the efficacy of ASCT in patients with R/R LBCL after a long-term follow up and try to define the optimal role of ASCT. Patients and methods: We performed a retrospective multicenter study based on GETH-TC database of ASCT. We included patients from centers of GETH-TC/GELTAMO with R/R LBCL who underwent ASCT from January 2010 to December 2021. All the patients received rituximab and anthracycline-based frontline therapy. Diffuse LBCL NOS, high-grade B-cell lymphoma double/triple hit and NOS, primary mediastinal, transformed follicular lymphoma (tFL) and other less frequent LBCL subtypes were included. Plasmablastic and primary central nervous system lymphoma were excluded. Patients who underwent ASCT in first CR were also excluded except patients with tFL who had received previous anthracycline-based frontline therapy for the indolent lymphoma. The primary endpoints were progression-free survival (PFS) and overall survival (OS) in the overall series and according to different prognostic factors, including disease status at ASCT. Disease status was defined as complete remission (CR), partial response (PR) and refractory disease (stable disease or progression) assessed by PET/CT. Results: Seven-hundred and ninety-one patients fulfilled the inclusion criteria. Patients characteristics are summarized in Table 1. After a median follow-up of 74 months (95%CI 68-81), 65% of the patients were alive and 84% of them free of disease. Six-year-PFS and OS were 51% (95%CI 47-54) and 63% (95%CI 60-67), respectively. Non-relapse mortality at 1 year was 9% (95%CI 7-11). The main causes of death were progression in 161 (58%), ASCT-related toxicity in 18 (6%) and other causes in 98 (35%). PFS was significantly influenced by age at ASCT, treatment lines prior to ASCT and disease status at ASCT (p&amp;lt;0.01). OS was influenced by age at diagnosis, R-IPI at diagnosis, age at ASCT, treatment lines prior to ASCT and disease status at ASCT (p&amp;lt;0.01). In the multivariate analysis, age &amp;gt;60 years at ASCT [HR 1.31 (95%IC: 1.06-1.62), p=0.011], ASCT as ≥3 th line [HR 1.81 (95%IC: 1.42-2.31), p&amp;lt;0.001] and PR versus CR at ASCT [HR 1.46 (95%IC: 1.18-1.81), p&amp;lt;0.001] were the only independent variables influencing PFS, Figure 1. Age &amp;gt;60 years at ASCT [HR 1.62 (95%IC: 1.24-2.12), p&amp;lt;0.001], ASCT as ≥3 th line [HR 1.77 (95%IC: 1.32-2.37), p&amp;lt;0.001] and PR versus CR at ASCT [HR 1.58 (95%IC: 1.22-2.05), p&amp;lt;0.001] were the only independent variables for OS. From 307 (39%) patients who relapsed after ASCT, 59 received CART therapy (median PFS 8.9 months) and 69 allo-SCT (median PFS 10.8 months). Refractory disease or early relapse did not significantly influenced survival. Analyzing this population separately (n=477), disease status at ASCT (PR versus CR) and ASCT as ≥3 th line were the only independent variables for both PFS [HR 1.46 (95%IC: 1.11-1.92), p=0.007; HR 1.79 (95%IC: 1.32-2.43), p&amp;lt;0.001, respectively] and OS [HR 1.92 (95%IC: 1.38-2.67), p&amp;lt;0.001; HR 1.91 (95%IC: 1.35-2.69), p&amp;lt;0.001, respectively]. Conclusions: To our knowledge, this is the largest series analyzing the efficacy of ASCT in patients with R/R LBCL after rituximab-containing frontline therapy. Our results indicate that ASCT is a curative option for patients with chemosensitive disease (especially in CR after salvage), regardless of the timing of relapse after frontline treatment. These data support that ASCT could be considered in patients with primary refractory or early relapse, provided the disease is sensitive to salvage therapy.

CNSC-36. INDOLENT INTRAVASCULAR LARGE B-CELL LYMPHOMA (IVLBCL) ORIGINALLY PRESENTING AS A STROKE MIMIC

Abstract BACKGROUND IVBCL is a rare subtype of extranodal diffuse large B-cell lymphoma, characterized by the growth of neoplastic cells in blood vessels with no other apparent extravascular mass, making diagnosis a challenge. It usually has an aggressive and fast-paced course; however, there is limited data regarding incidence due to its rarity. CASE A 73 year-old woman presented with progressive gait worsening a year prior to presentation to our institution. Her symptoms then developed to include left-sided hemiparesis with associated headaches, warranting a local emergency department visit. Brain magnetic resonance imaging (MRI) without contrast showed a Flair hyperintense lesion in the right MCA territory with restricted diffusion, assumed to be an ischemic stroke, and she was started on stroke prevention measures. The patient continued to decline, becoming wheelchair-bound and developing short-term memory loss, chronic headaches, and pseudobulbar affect. Repeat brain MRI without contrast five months later showed progression of the Flair hyperintensity to the left hemisphere with restricted diffusion. Brain MRI with contrast followed, revealing subtle enhancement. Vessel imaging was unremarkable, and cerebrospinal fluid (CSF) analysis was normal with negative cytology and flow cytometry, yet elevated beta-2-microglobulin at 3.25 mcg/mL. A year after symptoms onset, the patient presented to our Neuro-Oncology clinic. Repeat Brain MRI with contrast and spectroscopy showed progression on the left-sided lesion with persistent restriction diffusion and enhancement, prompting a biopsy. Pathology confirmed large B cell lymphoma. PET-CT body scan showed no evidence of systematic disease. The patient was treated with Rituximab, Methotrexate, Vincristine, and Procarbazine (RMVP) with complete response demonstrated by complete resolution of the diffusion restriction and symptoms improvement. CONCLUSIONS Although IVLBCL is known for being a fast progressive disease, we present a case of indolent course delaying diagnosis. Unexplained progressive neurological symptoms with restricted diffusion on MRI should prompt consideration for this diagnosis.

Expression of the immune checkpoint molecules PD‑L1 and PD‑1 in EBV‑associated lymphoproliferative disorders: A meta‑analysis.

Epstein-Barr virus (EBV) has been implicated in the development of a wide range of lymphoproliferative disorders. In this process, the role of programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) has remained to be clarified. A meta-analysis of 20 studies was performed and risk ratios (RRs) with 95% confidence intervals (CIs) were used to evaluate the association between PD-L1/PD-1 expression and the status of EBV infection. The results showed that the expression level of PD-L1 in tumor cells was significantly higher in EBV+ cases with a pooled RR of 2.26 (95% CI, 1.63-3.14; P<0.01), particularly in subtypes of diffuse large B-cell lymphoma (DLBCL) and classical Hodgkin lymphoma. Similarly, EBV infection increased the expression of PD-L1 in immune cells with a pooled RR of 2.20 (95% CI, 1.55-3.12; P<0.01). In subtypes of DLBCL and post-transplant lymphoproliferative disorder, the expression of PD-L1 in immune cells is increased in EBV+ cases. Regarding the expression level of PD-1 in tumor-infiltrating lymphocytes (TILs), no significance was found between EBV infection and PD-1 expression, with a pooled RR of 1.10 (95% CI, 0.81-1.48; P>0.05). The present meta-analysis demonstrated that in EBV-associated lymphoproliferative disorders, EBV infection was associated with the expression level of PD-L1 in tumor cells and immune cells but was not associated with the expression of PD-1 in TILs.

Outcomes of High-Grade B-Cell Lymphoma As Compared to Other Large B-Cell Lymphoma Subtypes in Patients Treated with CD19-Directed CAR-T Cells at 3 rd Line or More. a Lysa Study Based on the French Descart-Registry.

Introduction : High-Grade-B-cell Lymphoma with MYC and BCL2 and/or BCL6 rearrangements (HGBL double hit [HGBL-DH] or HGBL triple hit [HGBL-TH]), or not otherwise specified (HGBL NOS), are distinct subtypes among Large B-Cell lymphoma (LBCL) considered to be more aggressive diseases. These entities are often resistant to standard chemotherapy (Landsburg, JCO, 2017). CAR-T cell therapy (CAR-T) have changed the treatment landscape of LBCL in chemo resistant LBCL in 3 rd line, and more recently in 2 nd line of treatment. Prognosis with CAR-T seems to be as good in HGBL as in other LBCL subtypes. (Neelapu, NEJM, 2017; Schuster, NEJM, 2019; Zurko, ASH 2022). However, Fluorescence In Situ Hybridation (FISH) study isn't systematically done at diagnosis leading to an underestimation of the diagnosis of HGBL. The aim of this study was to compare the prognosis of a large cohort of patients with HGBL versus other LBCL subtypes, characterized with FISH at diagnosis, in a real life setting, based on the French DESCAR-T registry (NCT04328298). Methods : We collected clinical and pathological data of patients treated for relapsed/refractory LBCL or HGBL in third line or more. Data were collected both at the time of the decision of treatment in multidisciplinary meeting (MDM) and at the time of CAR-T cell infusion. Histology other than de-novo LBCL were excluded. All patients should have been studied with FISH at least with MYC probe. If a MYC rearrangement was identified, a BCL2 and/or BCL6 rearrangement should have been characterized. A p-value &amp;lt;0.05 was significant. Results : Between January 2018 and November 2022, 228 patients meeting the inclusion criteria were included across 14 centers, 73 with HGBL (28 HGBL-DH with MYC- BCL2 rearrangement, 8 HGBL-DH with BCL6 rearrangement, 14 HGBL-TH, 23 HGBL NOS) and 155 with non-HGBL (LBCL with [n=19] or without [n=136] MYC rearrangement). Characteristics of patients with HGBL vs non-HGBL at eligibility for CAR-T and at infusion of CAR-T cells were similar with no statistical difference. At the time of CAR-T treatment decision, median age was 62 years and the others characteristics were as follows in patients with HGBL vs patients with non-HGBL : ECOG&amp;gt;=2: 9 (12 %) vs 23 (15%), LDH &amp;gt; 1N : 52 (71%) vs 119 (77%) and Ann Arbor stage III-IV : 63 (86%) vs 125 (81%). Median number of prior lines of treatment was 2 (maximum 7 in HGBL vs maximum 9 in non-HGBL). Among the population, 60 (82%) HGBL and 135 (87%) non-HGBL patients received CAR-T cell therapy. In non-treated patients : 5 (39%) vs 8 (40%) had a disease progression and 3 (23%) vs 7 (35%) died. In treated patients, 55 (92%) HGBL vs 126 (93%) non-HGBL received at least one bridging therapy before CAR-T infusion ; and response to bridging therapy was similar among them : 19 (35%) patients with HGBL were in complete or partial response vs 46 (37%) with non-HGBL. Characteristics of treated patients at time of infusion were also similar and as follows in HGBL patients vs non-HGBL patients : 16 (27%) vs 34 (25%) had bulky disease and 16 (27%) vs 31 (23%) had an elevated CRP. 23 (38%) vs 45 (33%) were treated with Tisa-cel and 90 (67%) vs 37 (62%) were treated with Axi-cel. The frequency of Cytokine Release Syndrome (CRS) and Immune effector-Cell Cytotoxicity Syndrome (ICANS) (including grade &amp;gt;=3) did not significantly differ : 56 (93%) patients with HGBL vs 114 (84%) patients with non-HGBL presented CRS and 23 (38%) vs 55 (41%) presented ICANS. Interestingly, more patients were admitted in ICU in the HGBL cohort : 21 (35%) vs 23 (17%) (p=0.009). Macrophage Activation Syndromes was reported for 2 HGBL patients (3%). Median follow-up was 20.5 [95 CI, 19.2-25.5] months from eligibility decided in MDM and 18.5 m [95CI, 14.3-23.4] from infusion. Progression free survival (PFS) and Overall survival (OS) were similar in both groups. Since eligibility, median OS was 7.6 m [95 CI, 6.4-18.3] for HGBL patients vs 11.8 m [95 CI, 9.5-22] for non-HGBL (p = 0.062). Since infusion, median PFS was 3.2 m [95CI, 2.8-6.0] for HGBL patients vs 4.5 m [95CI, 3.1-8.7] for non-HGBL (p = 0.103) Figure 1 and median OS was 15.4 m [95CI, 5.6-32.4] for HGBL patients vs 18.3 m [95CI, 8.5-not reached] for non-HGBL (p = 0.214). Figure 2 Conclusion : CAR-T cell therapy used in third line or more seems to overcome the poor prognosis of HGBL subtypes as compared to other LBCL subtypes, all characterized with FISH. This observation supports the interest to evaluate the potential benefit of CAR-T earlier in the course of the disease.

Second Vs Third Line Treatment with Axicabtagene Ciloleucel for Large B Cell Lymphoma - a Real-Life National Multicenter Retrospective Cohort Study with Propensity Score Matching

Background: Superiority of Axicabtagene Ciloleucel (Axi-Cel) in relapsed/refractory (R/R) large B cell lymphomas (LBCL) compared with standard of care was shown in both the 3 rd and 2 nd line setting. However, optimal timing for incorporation of CAR-T is not well established. We aimed to compare efficacy, toxicity profile, and product kinetics of Axi-Cel as 2 nd vs 3 rd line of treatment. Methods: we performed a national real world retrospective study of consecutive patients treated with Axi-Cel as 2 nd line with propensity score-matched patients treated with 3 rd line treatment. Patients were matched for age (±2 years), Eastern Cooperative Oncology Group (ECOG) performance status, and disease status at lymphodepletion. Disease status and response were defined by the Lugano criteria, cytokine release syndrome (CRS) and immune effector cells-associated neurotoxicity syndrome (ICANS) were defined by ASTCT Consensus (2019) and progression-free survival (PFS) was calculated from infusion to index event. Immunophenotyping from peripheral blood at day 7+ was used to analyze expansion of CAR-T cells. Results: Between 01/2019and 06/2023, 44 patients treated with Axi-Cel fulfilled the inclusion criteria, 22 in each cohort. Groups were well matched in the propensity score domains (mean difference 2, p=.65 for age, mean square .32, p=.57 for ECOG, and mean square .26, p=.61 for disease status at lymphodepletion). Median follow up was 2.2 (range, 1-28.8) months in 2 nd line group and 10.8 (range, 1-39) months in the 3 rd group. Median age was 68 (range, 39 - 84) and 66 (range, 32 - 80) years in the 2 nd and 3 rd line groups, respectively. There were no differences between gender (p=.76), LBCL subtypes (p=.16), % of patients receiving bridging therapy (p=.55), % of patients with elevated LDH levels prior to lymphodepletion (p=.98), and n days from collection to treatment (p=.29) between the 2 groups. There was a lower % of patients with primary refractory disease in the 2 nd, compared to 3 rd line therapy group (63% vs. 36%, respectively, p=.09) and a higher % of patients with transformed disease (42% vs. 14%, respectively, p=.04). Both overall and grade 3-4 incidences of CRS were similar between the 2 nd line and the 3 rd line groups (86% vs. 95%, p=.16 and 18% in both groups, p=1, respectively). Median days to CRS onset was also similar (1, range 0 - 5 and 2, range 0 - 7, p=.1, respectively). Both overall and grade 3-4 incidences of ICANS) were similar between the 2 nd line and the 3 rd line groups (41% vs. 64%, p=.48 and 14% vs. 18%, p=.73, respectively. Median days to ICANS onset was lower in the 2 nd line compared to the 3 rd line group (4, range 0 - 8 and 6, range 0 - 7, p=.06, respectively). There were no differences between the groups in the median tocilizumab doses (p=.21), % of patients receiving steroids (p=.12), cumulative steroids dose (p=.17), % of patients receiving growth factors (p=1), and duration of admission (p=.51). Median day +7 CAR-T blood levels were higher in the 2 nd line compared to the 3 rd line group (126 (range,1-791) vs. 18.1 (range, 0-988) cells/microL, p=.05, respectively). 1-month overall response rate (ORR) was 86% (CR=77%) in the 2nd line group vs 64% (CR=45%), in the 3rd line group, p=.081 Figure 1a. Three-months progression-free survival was 88% (95%, CI 64%-100%) vs. 59% (45%-73%), respectively, Figure 1b. Cox regression identified 2 nd line treatment associated with better progression-free survival (HR=.15, p=.007) and progressive disease at lymphodepletion associated with worse progression-free (HR=8.5, p=.007), while age, gender, and ECOG performance status did not impact progression. Conclusions: This matched comparison showed favorable ORR and PFS rates when Axi-Cel is utilized as a 2nd line treatment vs 3rd line. Toxicity profile is similar. Higher CAR-T expansion in the 2nd line might provide insight regarding product quality and exhaustion phenotype when manufactured earlier in the LBCL treatment course. A longer follow-up is needed to test whether these findings translate to durable remission and cure.

Whole Exome Sequencing Analysis of Diffuse Large B-Cell Lymphoma That Progressed to Central Nervous System

Background: Recent sequencing analyses have identified distinct genetic subtypes of diffuse large B-cell lymphoma (DLBCL). The MCD subtype, characterized by MYD88 L265P and CD79B gene mutations, is frequently found in DLBCL that progresses to the central nervous system (CNS), known as secondary CNS lymphoma (sCNSL) (Ollila, Blood 2021). In addition, the MCD subtype is also frequently found in primary CNS lymphoma (PCNSL) (Radke, Nat commun 2022). Therefore, we hypothesized that specific genetic alterations that are present in the initial DLBCL tumors are associated with their progression to the CNS. We aimed to investigate i) the clinical impact of genetic subtypes of DLBCL and ii) genomic mutations that may be associated with sCNSL. To this end, genetic alterations in DLBCL samples at diagnosis that later developed into sCNSL were evaluated using whole-exome sequencing (WES). Methods: A total of 44 patients with DLBCL who developed sCNSL after receiving standard rituximab-containing chemotherapy between 2009 and 2020 were identified from five institutions. sCNSL was diagnosed on the basis of imaging and/or pathological findings. Genomic DNA (gDNA) was extracted from formalin-fixed, paraffin-embedded tumor samples obtained at the initial diagnosis of DLBCL. Finally, 26 of the 44 samples with sufficient gDNA were subjected to WES at BGI Genomic Co. Ltd. Single-nucleotide variants and short indels were detected using Mutect2 and filtered as described in Figure 1. Genetic subtypes were determined using the LymphGen algorithm (https://llmpp.nih.gov/lymphgen/index.php). The association between the clinicopathological features and genetic subtypes was also evaluated. In addition, recurrently mutated genes (&amp;gt;10% in our cohort) were identified and their alteration frequencies were compared with those in a representative general DLBCL cohort (N=574, available in the article by Schmitz, NEJM 2018) and PCNSL cohort (N=30, whole genome sequencing performed, available in the article by Radke, Nat Commun 2022) (Figure 1a). Results: The median age of the 26 patients was 69 years (range, 34-87). At the time of CNS progression, 54, 27, and 19% of the patients had parenchymal CNS disease, extraparenchymal CNS disease, and both, respectively. Immunohistological analysis showed that the non-germinal center B-cell-like (GCB) type, as defined using the Hans algorithm, and dual expression of MYC and BCL2 (DEL) were identified in 65% and 69% of patients, respectively. The median overall survival (OS) from CNS relapse was 16 months (95% confidence interval, 2-30). WES analysis showed that the median mean coverage depth of the 26 samples was 140 (range, 53-299). The median mapping rate was 94% (range, 80-99). As expected, the most frequently mutated genes in our cohort were MYD88 (50%), PIM1 (50%), BTG2 (31%), and CD79B (31%), corresponding to the MCD subtype. The LymphGen algorithm classified the 26 samples into MCD (n=12, 46%), EZB (n=5, 19%, including one with a composite feature of ST2), BN2 (n=1, 4%) and “not classified” (n=8, 31%) (Figure 1b). The CNS-IPI risk, DEL status, and CNS relapse sites did not differ among the genetic subgroups. In addition, univariate analysis showed that non-GCB status, DEL status, and genetic subtype at initial diagnosis did not influence OS. Next, we shortlisted 38 genes whose mutations were identified in three or more samples (&amp;gt;10%) of our cohort as well as in &amp;gt;10% of the PCNSL cohort (by Radke, Nat Commun 2022). We further selected genes that were less frequent (&amp;lt;3%) in the general DLBCL cohort and identified several genes, such as MUC16 and FAT4, that were more enriched in PCNSL and our sCNSL cases (Figure 1a). Metascape analysis (https://metascape.org/gp/index.html#/main/step1) revealed that the top three enriched processes associated with these genes were sensory organ development, cell adhesion via plasma membrane adhesion molecules, and morphogenesis of epithelium. Conclusion: Our study confirmed that MCD was a major genetic subtype of DLBCL that developed sCNSL. We identified recurrently mutated genes that were common in both sCSNL and PCNSL but not in the general DLBCL cohort; these genes may be associated with CNS progression. Validation of our results and investigation of the functions of these genes will help to understand the mechanisms of CNS relapse and develop more accurate markers to predict sCNSL. *Suzuki T and Yokomori R equally contributed to this study.

Baseline 18f-Fluorodeoxyglucose PET/CT Radiomics Predicts Outcome in Newly Diagnosed Intravascular Large B-Cell Lymphoma

[Introduction] Treatment outcomes of intravascular large B-cell lymphoma (IVLBCL), a rare subtype of extra-nodal diffuse large B-cell lymphoma (DLBCL), have dramatically improved in recent years. However, prognostic factors for IVLBCL are largely unknown. Several studies have explored the potential of the baseline 18F-fluorodeoxyglucose (FDG) PET/CT radiomics features to identify patients with poor prognosis. For example, metabolic tumor volume (MTV) reflects the FDG-avid tumor burden, and the maximum distance between the largest lesion and any other lesion quantifies the dissemination of the tumor, and both factors are inversely related to overall survival (OS) and progression-survival (PFS) in DLBCL. In this study, we explored prognostic impact of FDG PET/CT radiomics features in newly diagnosed IVLBCL. [Methods] We retrospectively evaluated patients with histopathologically proven newly diagnosed IVLBCL according to the 2008 World Health Organization criteria between January 2010 through February 2022 from hospitals participating in the North Japan Hematology Study Group (NJHSG). Quantitative analysis of all FDG PET/CT was performed using Metavol (Hokkaido University, Sapporo, Japan), with exclusion of physiological accumulation. MTV was defined as the volume of lymphoma lesions visualized on PET/CT scans with standardized uptake value (SUV) peaks greater than or equal to hepatic SUV peak. To quantify the dissemination of the tumor, we calculated the number of the body areas (head-neck, chest, abdomen, upper-extremities, lower-extremities) having BM lesions with a higher SUV peak than liver SUV peak. Patients with BM lesions spread across 4-5 areas were defined as cases having widely disseminated lesions (WDL). Progression-free survival (PFS) was defined as the time from the start of treatment to the first of progression, relapse, or death from any cause. Patients undergoing upfront autologous stem-cell transplantation (auto-SCT) were censored at the time of transplantation. [Results] We identified fifty-two IVLBCL patients (age 30-89 years, median 65 years; 57.7% male) who performed FDG PET/CT at diagnosis. Twenty-eight patients (54.9%) had poor performance status (ECOG PS ≥2), and 49 patients (94.2%) showed stage III-IV. Forty-nine patients (94.2%) had 2 or more extranodal involvement. Elevated serum LDH level was observed in 49 cases (94.2%) (median, 623.5 IU/L; range, 147-4907 IU/L). The median serum levels of soluble IL-2 receptor (sIL-2R), ferritin, and C-reactive protein (CRP) were 4496.5 IU/mL (range, 321-19900 IU/mL), 655.15 ng/mL (range, 50-6657 ng/mL), and 6.905 mg/dL (range, 0.11-25.86 mg/dL), respectively. The median MTV was 415.527 cm 3 (range, 0-3000 cm 3). ROC analysis revealed that the cutoff value of the MTV &amp;gt; 388 cm 3 could predict progression events within 2 years. Area under curve was 0.71 (95% CI: 0.564-0.857). Twenty-nine patients (55.8%) were classified as having MTV &amp;gt; 388 cm 3 (high MTV). Twenty-three patients (44.2%) had WDL. Fifty-one (98.1%) patients received chemotherapy, all of which was rituximab-containing regimen. Three patients (5.8%) received upfront auto-SCT. Median follow-up duration was 48.8 months (range, 5.8-140.5 months) in survivors. Age, LDH level, number of extranodal lesions, clinical stage, and PS did not affect OS and PFS. Although the high MTV and WDL did not significantly affect OS ( P = 0.095, P = 0.173, respectively; Log-rank), these findings did correlate significantly with poor PFS ( P = 0.011, P = 0.042, respectively; Log-rank). Thus, we defined a high MTV or a WDL as poor PET findings. Thirty-two patients had poor PET findings. Importantly, patients with poor PET findings showed significantly poor OS and PFS compared to patients without (2-year OS: 71.2% vs. 93.3%, P = 0.015, 2-year PFS: 45.5% vs. 93.8%, P = 0.001; Log-rank, Fig. 1, 2). [Conclusion] This is the largest study to assess prognostic impact of FDG PET/CT radiomics features on newly diagnosed IVLBCL. Poor PET findings were significantly correlated with worse OS and PFS.