Value Of Metabolic Tumor Volume Research Articles

Correlation of PSA blood levels with standard uptake value maximum (SUVmax) and total metabolic tumor volume (TMTV) in 18F-PSMA-1007 and 18F-choline PET/CT in patients with biochemically recurrent prostate cancer.

In this prospective study, we investigated the correlation between prostate-specific antigen (PSA) levels in the blood of patients with prostate cancer in biochemical recurrence after radical treatment with the semiquantitative parameters standard uptake value maximum (SUVmax) and the total metabolic tumor volume (TMTV) in the metastatic foci depicted in 18F-prostate-specific membrane antigen (PSMA)-1007 and 18F-choline PET/computed tomography (CT) imaging. We prospectively examined 104 patients with biochemical relapse of prostate cancer after primary definitive treatment. All patients underwent one 18F-PSMA-1007 and one 18F-choline PET/CT examination in randomized order within a time frame of 10 days and were followed for at least 6 months (182 ± 10 days). The semiquantitative parameters of SUVmax and metabolic tumor volume (MTV) of each neoplastic lesion in PET/CT imaging were calculated, and further summation of each MTV value was done to calculate the TMTV. According to the Spearman correlation analysis, a positive correlation was found between PSA levels and SUVmax and TMTV scores in the metastatic foci of 18F-PSMA-1007 PET/CT (r = 0.24 and 0.35, respectively; P < 0.05) and SUVmax in the lesions of 18F-choline PET/CT (r = 0.28; P < 0.0239). However, a positive but NS correlation was demonstrated between values of PSA and TMTV for each lesion in the 18F-choline PET/CT study (r = 0.22; P = 0.0795). The detection rate of the different PSA levels with a cutoff of 1 ng/ml was higher for 18F-PSMA-1007 than 18F-choline. In biochemical relapse patients there is a positive correlation between PSA levels in the blood and the semiquantitative parameters SUVmax and TMTV of the metastatic foci in the 18F-PSMA-1007 and 18F-Choline PET/CT imaging.

Abstract PO3-27-01: Prediction of pathological complete response to neoadjuvant treatment in loco-regional advancedbreast cancer by using advanced PET/CT metabolic parameters

Abstract Prediction of pathological complete response to neoadjuvant treatment in loco-regional advanced breast cancer by using advanced PET/CT metabolic parameters. Abstract: Background: The standard treatment for locally advanced breast cancer (LABC) is neoadjuvant systemic therapy followed by surgery. The usefulness of FDG PET/CT for evaluating the treatment efficacy in breast cancer is well established; however, the role of quantitative functional PET/CT parameters, such as the metabolic tumor volume (MTV) and total lesion glycolysis (TLG), remains inconclusive. The aim of this study was to determine the correlation between quantitative functional parameters derived from PET/CT in LABC patients at staging and the response to neoadjuvant therapy. Methods: Seventy-eight consecutive patients (aged 25-82 y) with confirmed LABC (stages II-III) who underwent PET/CT as a part of their staging assessment and received neoadjuvant therapy followed by surgery were retrospectively included in this study. All patients underwent an FDG PET/CT at staging; and values of SUV max, SUV mean, MTV, and TLG were determined from the PET/CT studies. The patients were divided into two groups, based on the completeness of histopathologic response to neoadjuvant therapy, both in the primary tumor and axillary lymph nodes. Clinical, imaging and demographic data were collected from patient’s medical record. Results: A complete pathologic response (pCR) was achieved in 33/78 (42%) patients. Among patients with ER/PR positive, Her2-neu negative tumors, in 23/27 (85%) patients only partial pathologic response was reached; 91% of patients with ER/PR negative, Her2-neu positive and 43% of Triple-negative patients had complete pathological? response. For the primary breast tumor response, a higher SUV max, 10.7±5.34 for pCR vs. 7.24±4.62 for non-pCR group was measured, p-value=0.003; threshold value of 6.625. A higher SUV mean in the primary tumor resulted in a significantly higher rate of pCR, 5.95±2.36 vs 4,4±2.16, p=0.004, with a threshold value of 5.795. Neither MTV, not TLG were predictive parameters of the primary tumor response. For lymph nodes response, SUV max and SUV mean had no role in the prediction of pCR. Statistically significant difference however, was found between pCR and non-pCR in MTV values in the involved lymph nodes, with a median =2.13 cm³ [0-7.85] in pCR group vs 5.43 cm³ [3.11-15.3] in non-pCR, p=0.01 (threshold value 2.375) as well as in TLG measurements, with a median of 4.64 [0-19.8] vs. 12.7 [3.21-23.1], p=0.047, (25-75 IQR). Conclusion: Primary breast tumor SUV max/mean values have a significant correlation with the treatment response and threshold values were found. Low MTV and TLG measurements in lymph nodes may predict pCR. Neither MTV nor TLG had were found to have a significant role in the prediction of the primary tumor response. Citation Format: Maisun Shamya, Olga Kagna, Zohar Keidar, Tala Palchan-Hazan, Salem Billan, Roxolyana Abdah-Bortnyak. Prediction of pathological complete response to neoadjuvant treatment in loco-regional advancedbreast cancer by using advanced PET/CT metabolic parameters [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-27-01.

Association Between Pretreatment 11C-Methionine Positron Emission Tomography Metrics, Histology, and Prognosis in 125 Newly Diagnosed Patients with Adult-Type Diffuse Glioma Based on the World Health Organization 2021Classification

To clarify the relationships between 11C-methionine (MET) positron emission tomography (PET) metrics and the histology, genetics, and prognosis of adult-type diffuse glioma (ADG) based on the World Health Organization (WHO) 2021 classification. A total of 125 newly diagnosed patients with ADG were enrolled. We compared the maximum standardized uptake value (SUVmax), tumor-to-normal background ratio (TNR), metabolic tumor volume (MTV), and total lesion methionine uptake (TLMU) to the histology and genetics of the patients with ADG. We also evaluated the prognoses of the 93 surgically treated patients. The patients with isocitrate dehydrogenase wild ADG showed significantly higher MET-PET metrics (P < 0.05 for all parameters), significantly shorter overall survival and progression-free survival (P < 0.0001 for both) than those of the patients with isocitrate dehydrogenase mutant (IDHm) ADG. In the IDHm ADG group, the SUVmax, MTV, and TLMU values were significantly higher in patients with IDHm grade (G) 4 astrocytoma than patients with IDHm G2/3 astrocytoma (P < 0.05 for all), but not than patients with G2-3 oligodendroglioma. The progression-free survival was significantly shorter in the patients with G4 astrocytoma versus the patients with G2/3 astrocytoma and G3 oligodendroglioma (P < 0.05 for both). The SUVmax and TNR values were significantly higher in recurrent patients than nonrecurrent patients (P < 0.01 for both), but no significant differences were found in MTV or TLMU values. MET-PET metrics well reflect the histological subtype, WHO grade and prognosis of ADG based on the 2021 WHO classification, with the exception of oligodendroglial tumors. Volumetric parameters were not significantly associated with recurrence, unlike the SUVmax and TNR.

Total lesion glycolysis by 18F-fluorodeoxyglucose positron emission tomography predicts tumor aggressiveness in patients with extrahepatic bile duct carcinoma.

18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) parameters are prognostic factors in multiple malignancies. However, the prognostic value in bile duct carcinoma is unclear. We evaluated the impact of metabolic parameters of 18F-FDG-PET/CT in resectable extrahepatic bile duct carcinoma. We retrospectively reviewed the records of 100 patients with extrahepatic bile duct carcinoma who had undergone 18F-FDG-PET/CT and subsequent surgical resection between January 2017 and January 2023. We calculated maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) and investigated their prognostic significance. The optimal cutoff values of SUVmax, MTV, and TLG for predicting overall survival (OS) after surgery were 3.88, 3.55 and 7.55, respectively. In multivariate analysis, each metabolic parameter influenced both OS and recurrence-free survival (RFS). TLG showed the lowest Akaike information criteria statistic value, indicating that it had the best ability to predict OS and RFS. High TLG was significantly associated with the number of lymph node metastases and poorly differentiated type. Patients with high TLG showed poorer RFS and OS, which were significantly worse than in those with low TLG. Tumor TLG predicted tumor malignancy potential and could be a useful prognostic predictor for extrahepatic bile duct carcinoma.

Volume-based 18F-FDG PET/CT predicts prognosis and outcome of active surveillance for intra-abdominal desmoid tumor.

Desmoid tumor (DT) is a rare monoclonal, fibroblastic proliferation characterized by a variable and often unpredictable clinical course. Initial active surveillance is recommended by current guideline, and surgery is one of the main therapies for DT. Predicting the prognosis and outcome of active surveillance for intra-abdominal DT is pressing issue. The study included eighteen patients with intra-abdominal DT. Metabolic tumor volume (MTV), total lesion glycolysis (TLG), and maximum standardized uptake value (SUVmax) were measured. We analyzed their relationship with the outcome of active surveillance, as well as clinical, prognostic, and pathological data. The MTV and TLG of recurrent DT were significantly higher than those of non-recurrent DT (P < 0.001 and P = 0.00, respectively). The ROC curve suggested that the appropriate cutoff values for distinguishing recurrent DT from non-recurrent DT were 760.8 for MTV (sensitivity = 1, specificity = 0.857 and AUC = 0.929), and 1318.4 for TLG (sensitivity = 1, specificity = 0.786, and AUC = 0.911). The cutoff values of MTV and TLG significantly correlated with PFS using the Kaplan-Meier method (P = 0.002 and P = 0.007, respectively). MTV and TLG could distinguish DTs with subsequent progression from stable ones (P = 0.004 and P = 0.004, respectively). The ROC curve suggested that the appropriate cutoff values for distinguishing DTs with subsequent progression from stable ones were 197.1 for MTV (sensitivity = 0.9, specificity = 1, and AUC = 0.900), and 445.45 for TLG (sensitivity = 0.9, specificity = 1, and AUC = 0.900). Volume-based 18F-FDG-PET can predict prognosis of intra-abdominal DT. MTV and TLG can predict the outcome of active surveillance for intra-abdominal DT. MTV and TLG can potentially be predictors of surgical risk and difficulty.

Evaluating therapeutic efficacy of extended shelf-life 90 Y glass microspheres in transarterial radioembolization for colorectal cancer: a quantitative FDG PET/CT analysis.

There is a lack of sufficient evidence regarding the use of extended shelf-life (ExSL) Yttrium-90 ( 90 Y) glass radiomicrospheres in metastatic colorectal cancer (mCRC) patients. We aimed to investigate the efficacy of ExSL 90 Y glass radiomicrospheres with a personalized treatment approach by analyzing 18 F-FDG PET/CT quantitative parameters [metabolic tumor volume (MTV) and total lesion glycolysis (TLG)] separately before and after the treatment. A total of 93 radioembolization sessions involving 77 patients were included. Simplicit 90 Y software was utilized to perform multicompartmental voxel-based dosimetry. Adverse events were recorded using the CTCAE v5.0 criteria. The survival data were recorded in detail. The overall disease control rate was 84.9%, with a median overall survival (OS) of 12.7 months and median progression-free survival (PFS) of 8.3 months. A statistically significant increase in treatment response rate was observed when there was an increase in absorbed tumor dose for pre-treatment unit MTV ( P = 0.005) and TLG ( P = 0.004) values. We didn't observe any additional side effects/vital risks that could be considered clinically significant. Our study has provided evidence on the therapeutic effectiveness and safety in terms of dose-toxicity profile of ExSL 90 Y glass microspheres in a large cohort of mCRC patients. With a personalized treatment approach, the increase in radiation dose absorbed by the tumor has shown a significant contribution to treatment response rate, as indicated by quantitative measurements obtained through 18 F-FDG PET/CT.

Analysis of PET-CT Derived Radiomic Biomarkers with Efficacy, Safety, and Expansion of Axicabtagene Ciloleucel (Axi-Cel) in Patients with Relapsed or Refractory Large B-Cell Lymphoma (LBCL)

Introduction In LBCL, the presence of bulky disease is known to be an adverse prognostic factor, indicating poorer outcomes. The ZUMA-1 clinical trial (Neelapu, NEJM 2017) showed that high tumor burden, as measured by the sum of the product of diameters (SPD), was associated with lower durable response after Chimeric Antigen Receptor T-Cell Therapy (CAR T ). Radiomic biomarkers such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG) have been recently studied to assess three-dimensional measurement of tumor activity and metabolic volume in LBCL. There is a paucity of understanding on the impact of radiomic biomarkers on outcomes and CAR T expansion kinetics in LBCL CAR T recipients. We studied the association of these radiomic biomarkers with efficacy, toxicity, and CAR T expansion in this single institution retrospective study of patients with LBCL who received axi-cel. Methods 189 patients with relapsed or refractory LBCL who were treated with axi-cel from 12/2017 to 5/2022 were studied. The closest PET-CT scan to CAR T leukapheresis date was identified for each patient. After excluding cases with unavailable pre-apheresis PET-CT scans, 172 patients were included in the statistical analysis. Two reviewers independently used a semi-automated contouring software (MIM, v. 7.1.2) to measure maximum standardized uptake value (SUV Max), mean SUV, total MTV and TLG values of malignant lesions. CD19 CAR T expansion was measured by real-time flow cytometry with anti-idiotype-FMC63 conjugated to Dylight 65013. Areas under the curve (AUCs) were calculated for CAR T expansion in the 28 days following infusion using the linear trapezoidal method on raw values, and the results were transformed using a base-10 logarithm. Patients were categorized into high and low biomarker groups based on whether their values exceeded or were below the respective median. For univariate analyses, continuous variables were compared using a Mann-Whitney U-test, categorical using a Chi-square test, and time-to-event using a log-rank test. Within a multivariable framework, regressions (linear, logistic, Cox) were fit to control for potential confounders. Results Median duration of follow up was 33 months (IQR: 17.9, 44.7). MTV was highly correlated with TLG (r=0.87). High MTV was associated with bulky disease defined as &amp;gt;10cm (p&amp;lt;0.01), high IPI at apheresis (p&amp;lt;0.04), bridging treatment (p&amp;lt;0.01), pre-lymphodepletion lactate dehydrogenase (p&amp;lt;0.01), and autologous stem cell transplant (p=0.02). Complete response (CR) rate was greater for those in the low MTV group (79.3%) compared to high MTV group (52.3%), (p&amp;lt;0.01), as well as those with high TLG (77.9%) compared to low TLG group (46%), (p&amp;lt;0.01). Low MTV was significantly associated with better progression free survival (PFS) in a univariate analysis (p=0.03); median PFS was 33.5 months (IQR 3.06, 39.55) for low MTV versus 6.1 months (IQR 6.38, NA) for high MTV. Low MTV was also significantly associated with better overall survival (OS) in a univariate analysis (p&amp;lt;0.01); median OS was not reached for the low MTV group but was 31.8 months for the high MTV group (IQR 16.5, NA) (Figure 1). After multivariable regression analysis, PFS was no longer different by MTV biomarker level ( p= 0.07), but OS was still significantly different ( p= 0.01). Neither PFS nor OS were significantly associated with the binary TLG variable. The proportion of cytokine release syndrome (CRS) or immune cell associated neurologic toxicity syndrome (ICANS) of any grade or severe grade ICANS were significantly higher for the high MTV and TLG groups as compared to their respective low groups. Length of stay was significantly longer for those in the high MTV and TLG groups (Table 1). A higher day 14 CAR T cell expansion was seen in the high TLG as compared to the low group (0.89 vs 0.63 cells/μL, p=0.002). However, there was no statistically significant difference in CAR T expansion as measured by AUC between the high and low MTV or TLG cohort. Conclusion Our study demonstrates poor outcomes for efficacy, safety, and healthcare utilization endpoints in patients with high tumor bulk as measured by volumetric tumor assessment on PET-CT. Furthermore, we show a differential peripheral day 14 CAR T expansion with higher expansion seen in patients with higher tumor bulk. Strategies like tumor debulking prior to CAR T therapy and earlier referral in patients with high tumor bulk may improve clinical outcomes.

Metabolic Tumor Volume from Baseline PET/CT Improves Stratification in the High IPI Risk Patients with Diffuse Large B‐Cell Lymphoma

Background: In the rituximab era, the international prognostic index (IPI) risk stratification was not enough to predict outcome in patients with diffuse large B cell lymphoma (DLBCL). Previous studies showed the Metabolic tumor volume（MTV） from baseline [ 18F]FDG PET/CT could be used to predict outcome. In this study, we evaluated the prognostic value of IPI and MTV in DLBCL patients. Patients and methods: A total of 262 de novo DLBCL patients who were treated with the R-like chemotherapy were retrospectively analyzed in this study. The IPI and MTV were compared to the Overall Survival (OS) and Progression Free Survival (PFS). Results: The MTV is better than TLG and SUVmax for predicting disease progression. The cutoff value of MTV was 444 cm 3. Patients with high MTV showed inferior OS and PFS ( p &amp;lt; 0.001, respectively). Although the IPI remains predictive it distinguishes only 2 risk groups, rather than the 4 groups originally described. Further analysis showed high MTV could identify a subgroup of patients with extremely inferior OS and PFS in high IPI risk patients ( p = 0.0089 and p= 0.024, respectively). Multivariate analysis revealed that high MTV is a significant poor prognostic factor for both OS (HR 3.168[1.81-5.56], p &amp;lt;0.001) and PFS (HR 2.637 [1.51-3.71], p &amp;lt;0.001). Conclusions: Our study suggests that MTV from baseline PET/CT is an important prognostic factor in DLBCL patients, allowing the identification of an inferior outcome subgroup in high-risk patients, which may help to guide treatment in clinical trial.

The relationship between 18F-FDG PET/CT parameters and histopathological-immunohistochemical properties in breast cancer

In this study, it is aimed to determine the correlation between histopathologic-immunohistochemical factors, tumor subtypes and fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) parameters such standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG) in breast cancer (BC). Initial PET/CT examination of 110 histopathologically proven BC patients (age ranging 27-92, mean age 56.18 ± 14.59) were included in this retrospective study. The relationship between histopathological-immunohistochemical factors, tumor subtypes and PET/CT parameters were analyzed by regression analysis. The mean SUV max value of 110 breast tumors was 7.73 ± 5.62 (range 1.4 - 34.15). Histological subtypes were; invasive ductal carcinoma (n:94, 85.5%), invasive lobular carcinoma (n=6, 5.5%) and other types (n=10, 9.1%). The distribution of BC subtypes was as follows; Luminal A (Lum A) (n=38; 34.5%), Luminal B (Lum B) (n=56; 50.9%), HER2-positive (n=3; 2.7%) and Triple Negative (TN) (n=13; 11.8%). Univariate regression analysis revealed significantly higher SUV max values in ductal carcinomas than lobular carcinomas (p=0.03). SUVmax values of the Lum B, HER2 positive and TN groups were higher than Lum A group (p=0.03, p&lt;0.001, p&lt;0.001 respectively). Univariate regression analyses also showed that the MTV and TLG values of TN group were significantly higher than Lum A group (p=0.011, p=0.007, respectively). In multivariate regression analyses, no significant difference was observed in above mentioned groups. MTV, TLG and SUVmax values significantly correlated with histopathological-immunohistochemical factors and tumor subtypes in BC. So that, these parameters can be used to predict the tumors’ behavior.

Application of an artificial intelligence-based tool in [18F]FDG PET/CT for the assessment of bone marrow involvement in multiple myeloma

Purpose[18F]FDG PET/CT is an imaging modality of high performance in multiple myeloma (MM). Nevertheless, the inter-observer reproducibility in PET/CT scan interpretation may be hampered by the different patterns of bone marrow (BM) infiltration in the disease. Although many approaches have been recently developed to address the issue of standardization, none can yet be considered a standard method in the interpretation of PET/CT. We herein aim to validate a novel three-dimensional deep learning-based tool on PET/CT images for automated assessment of the intensity of BM metabolism in MM patients.Materials and methodsWhole-body [18F]FDG PET/CT scans of 35 consecutive, previously untreated MM patients were studied. All patients were investigated in the context of an open-label, multicenter, randomized, active-controlled, phase 3 trial (GMMG-HD7). Qualitative (visual) analysis classified the PET/CT scans into three groups based on the presence and number of focal [18F]FDG-avid lesions as well as the degree of diffuse [18F]FDG uptake in the BM. The proposed automated method for BM metabolism assessment is based on an initial CT-based segmentation of the skeleton, its transfer to the SUV PET images, the subsequent application of different SUV thresholds, and refinement of the resulting regions using postprocessing. In the present analysis, six different SUV thresholds (Approaches 1–6) were applied for the definition of pathological tracer uptake in the skeleton [Approach 1: liver SUVmedian × 1.1 (axial skeleton), gluteal muscles SUVmedian × 4 (extremities). Approach 2: liver SUVmedian × 1.5 (axial skeleton), gluteal muscles SUVmedian × 4 (extremities). Approach 3: liver SUVmedian × 2 (axial skeleton), gluteal muscles SUVmedian × 4 (extremities). Approach 4: ≥ 2.5. Approach 5: ≥ 2.5 (axial skeleton), ≥ 2.0 (extremities). Approach 6: SUVmax liver]. Using the resulting masks, subsequent calculations of the whole-body metabolic tumor volume (MTV) and total lesion glycolysis (TLG) in each patient were performed. A correlation analysis was performed between the automated PET values and the results of the visual PET/CT analysis as well as the histopathological, cytogenetical, and clinical data of the patients.ResultsBM segmentation and calculation of MTV and TLG after the application of the deep learning tool were feasible in all patients. A significant positive correlation (p < 0.05) was observed between the results of the visual analysis of the PET/CT scans for the three patient groups and the MTV and TLG values after the employment of all six [18F]FDG uptake thresholds. In addition, there were significant differences between the three patient groups with regard to their MTV and TLG values for all applied thresholds of pathological tracer uptake. Furthermore, we could demonstrate a significant, moderate, positive correlation of BM plasma cell infiltration and plasma levels of β2-microglobulin with the automated quantitative PET/CT parameters MTV and TLG after utilization of Approaches 1, 2, 4, and 5.ConclusionsThe automated, volumetric, whole-body PET/CT assessment of the BM metabolic activity in MM is feasible with the herein applied method and correlates with clinically relevant parameters in the disease. This methodology offers a potentially reliable tool in the direction of optimization and standardization of PET/CT interpretation in MM. Based on the present promising findings, the deep learning-based approach will be further evaluated in future prospective studies with larger patient cohorts.

High values of baseline volumetric PET biomarkers in classical Hodgkin's lymphoma as predictors of unfavourable prognosis

Purpose: To analyse the prognostic value of the initial volumetric PET biomarkers – the total metabolic tumor volume (MTV) and the total lesion glycolysis (TLG) – in classic Hodgkin's lymphoma (cHL) and determine their optimal threshold values for prognosis.Material and methods. This retrospective study included 62 cHL patients with different stages who underwent staging with 18F-FGD PET/CT. The follow-up period was from 6 to 61 months after the baseline PET/CT, 41 patients remained in remission, 10 patients had refractory course, 11 relapsed. The examinations were processed with automatic (multi-foci segmentation – MFS) method to obtain MTV and TLG using two fixed absolute thresholds (SUVmax ≥ 2.5 and SUVmax ≥ 4.0) and one relative threshold (41% of SUVmax).Results. In subgroups with disease remission (n = 41) and refractory course or relapse (n = 21), statistically significant differences between MTV and TLG with the two thresholds were found – SUVmax ≥ 2.5 and 41% of SUVmax (p &lt; 0.05). When using threshold of SUVmax ≥ 4.0 statistically differences between the mean of MTV and TLG were no detected.Univariate analysis revealed correlation between progression-free survival and volumetric PET biomarkers (MTV and TLG) with three thresholds (SUVmax ≥ 2.5, SUVmax ≥ 4.0, and 41% of SUVmax).Conclusion. In cHL high values of initial volumetric PET biomarkers – MTV and TLG – calculated with three thresholds (SUVmax ≥ 2.5, SUVmax ≥ 4.0, and 41% of SUVmax) are associated with unfavourable prognosis – a high probability of refractory disease course or relapse.The optimal prognostic thresholds values of MTV and TLG in the analysed group were determined respectively: SUVmax ≥ 2.5 – 204 cm3 and 961, at 41% of SUVmax – 105 cm3 and 620.

Impact of tumour region of interest delineation method for mid-treatment FDG-PET response prediction in head and neck squamous cell carcinoma undergoing radiotherapy.

The aim of this study was to evaluate the impact of tumour region of interest (ROI) delineation method on mid-treatment 18F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) response prediction in mucosal head and neck squamous cell carcinoma during radiotherapy. A total of 52 patients undergoing definitive radiotherapy with or without systemic therapy from two prospective imaging biomarker studies were analysed. FDG-PET was performed at baseline and during radiotherapy (week 3). Primary tumour was delineated using a fixed SUV 2.5 threshold (MTV2.5), relative threshold (MTV40%) and a gradient based segmentation method (PET Edge). PET parameters SUVmax, SUVmean, metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated using different ROI methods. Absolute and relative change (∆) in PET parameters were correlated to 2-year locoregional recurrence. Strength of correlation was tested using receiver operator characteristic analysis using area under the curve (AUC). Response was categorized using optimal cut-off (OC) values. Correlation and agreement between different ROI methods was determined using Bland-Altman analysis. A significant difference in SUVmean, MTV and TLG values were noted between ROI delineation methods. When measuring relative change at week 3, a greater agreement was seen between PET Edge and MTV2.5 methods with average difference in ∆SUVmax, ∆SUVmean, ∆MTV and ∆TLG of 0.0%, 3.6%, 10.3% and 13.6% respectively. A total of 12 patients (22.2%) experienced locoregional recurrence. ∆MTV using PET Edge was the best predictor of locoregional recurrence (AUC =0.761, 95% CI: 0.573-0.948, P=0.001; OC ∆>50%). The corresponding 2-year locoregional recurrence rate was 7% vs. 35%, P=0.001. Our findings suggest that it is preferable to use gradient based method to assess volumetric tumour response during radiotherapy and offers advantage in predicting treatment outcomes compared with threshold-based methods. This finding requires further validation and can assist in future response-adaptive clinical trials.

Prognostic value of metabolic tumor volume and lesion dissemination from baseline PET/CT in patients with diffuse large B-cell lymphoma: Further risk stratification of the group with low-risk and high-risk NCCN-IPI

PurposeThe purpose of this study was to determine the prognostic value of metabolic tumor volume and lesion dissemination from baseline PET/CT in patients with diffuse large B-cell lymphoma (DLBCL) and the prognostic value of them in the National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI) subgroups. MethodsA total of 113 patients who underwent 18F-FDG PET/CT examination in our institution were retrospectively collected. The MTV was measured by iterative adaptive algorithm. The location of the lesion was obtained according to its three-dimensional coordinates, and Dmax was obtained. SDmax is derived from Dmax standardized by body surface area (BSA). The X-tile method was used to determine the optimal cut-off values for MTV, Dmax and SDmax. Cox regression analysis was used to perform univariate and multivariate analyses. Patient survival rates were derived from Kaplan-Meier curves and compared using the log-rank test. ResultsThe median follow-up time was 24 months. The median of MTV was 196.86 cm3 (range 2.54–2925.37 cm3), and the optimal cut-off value was 489 cm3. The median of SDmax was 0.25 m−1 (range 0.12–0.51 m−1), and the best cut-off value was 0.31 m−1. MTV and SDmax were independent prognostic factors of PFS (all P < 0.001). Combined with MTV and SDmax, the patients were divided into three groups, and the difference of PFS among the groups was statistically significant (P < 0.001), and was able to stratify the risk of NCCN-IPI patients in the low-risk (NCCN-IPI < 4) and high-risk (NCCN-IPI ≥ 4) groups (P = 0.001 and P = 0.031). ConclusionMTV and SDmax are independent prognostic factors for PFS in DCBCL patients, which describe tumor burden and tumor dissemination characteristics, respectively. The combination of the two could facilitate risk stratification between the low-risk and high-risk NCCN-IPI groups.

Prognostic value of metabolic tumor volume of extranodal involvement in diffuse large B cell lymphoma

Extranodal involvement predicts poor outcomes of diffuse large B cell lymphoma (DLBCL), but the impact of the metabolic tumor burden (MTV) of extranodal sites using positron emission tomography has not been clarified. This study aimed to assess the impact of extranodal MTV on overall survival (OS). We retrospectively analyzed 145 newly diagnosed DLBCL patients and verified the prognostic impact of each extranodal and nodal MTV. Multivariate Cox hazards modelling using both extranodal and nodal MTV as covariables identified extranodal MTV as a significant factor for OS (hazard ratio [HR] 1.072, 95% confidence interval [CI] 1.019–1.129, P = 0.008), but not nodal MTV. Multivariate Cox modelling using restricted cubic splines demonstrated that the impact of total MTV depends on the MTV of extranodal sites, not of nodal sites. When both the number and MTV of extranodal involvements were used as covariables, extranodal MTV remained a significant predictor of OS (HR 1.070, 95%CI 1.017–1.127, P = 0.009), but the number of extranodal sites did not. Extranodal MTV potentially had a more significant role on prognosis than nodal MTV. When considering prognostic impacts, the MTV of extranodal involvement is significantly more important than the number.

Prognostic value of baseline 18F-FDG PET/CT in patients with esophageal squamous cell carcinoma treated with definitive (chemo)radiotherapy

PurposeTo investigate the prognostic value of baseline 18F-FDG PET/CT in patients with esophageal squamous cell carcinoma (ESCC) treated with definitive (chemo)radiotherapy.MethodsA total of 98 ESCC patients with cTNM stage T1-4, N1-3, M0 who received definitive (chemo)radiotherapy after 18F-FDG PET/CT examination from December 2013 to December 2020 were retrospectively analyzed. Clinical factors included age, sex, histologic differentiation grade, tumor location, clinical stage, and treatment strategies. Parameters obtained by 18F-FDG PET/CT included SUVmax of primary tumor (SUVTumor), metabolic tumor volume (MTV), total lesion glycolysis (TLG), SUVmax of lymph node (SUVLN), PET positive lymph nodes (PLNS) number, the shortest distance between the farthest PET positive lymph node and the primary tumor in three-dimensional space after the standardization of the patient BSA (SDmax(LN-T)). Univariate and multivariate analysis was conducted by Cox proportional hazard model to explore the significant factors affecting overall survival (OS) and progression-free survival (PFS) in ESCC patients.ResultsUnivariate analysis showed that tumor location, SUVTumor, MTV, TLG, PLNS number, SDmax (LN-T) were significant predictors of OS and tumor location, and clinical T stage, SUVTumor, MTV, TLG, SDmax (LN-T) were significant predictors of PFS (all p < 0.1). Multivariate analysis showed that MTV and SDmax (LN-T) were independent prognostic factors for OS (HR = 1.018, 95% CI 1.006–1.031; p = 0.005; HR = 6.988, 95% CI 2.119–23.042; p = 0.001) and PFS (HR = 1.019, 95% CI 1.005–1.034; p = 0.009; HR = 5.819, 95% CI 1.921–17.628; p = 0.002). Combined with independent prognostic factors MTV and SDmax (LN-T), we can further stratify patient risk.ConclusionsBefore treatment, 18F-FDG PET/CT has important prognostic value for patients with ESCC treated with definitive (chemo)radiotherapy. The lower the value of MTV and SDmax (LN-T), the better the prognosis of patients.

The potential application of MR-derived ADCmin values from 68Ga-DOTATATE and 18F-FDG dual tracer PET/MR as replacements for FDG PET in assessment of grade and stage of pancreatic neuroendocrine tumors

BackgroundTo evaluate the utility of 68Ga-DOTATATE and 18F-FDG PET/MR for prediction of grade and stage of pancreatic neuroendocrine tumors (PNETs), and to examine the correlation between parameters obtained from FDG PET and diffusion-weighted imaging (DWI) MR parameters.MethodsA retrospective study using 68Ga-DOTATATE and 18F-FDG PET/MR imaging was performed between April 2020 and May 2022 on 46 individuals with histologically confirmed PNETs. Metabolic tumor volume (MTV), maximum standardized uptake value (FSUVmax), and tumor lesion glycolysis (TLG) for FDG; somatostatin receptor density (SRD), maximum standardized uptake value (GSUVmax), and total lesion somatostatin receptor density (TLSRD) for DOTATATE; and minimum and mean apparent diffusion coefficient (ADCmin and ADCmean) values for MRI, respectively. We performed Spearman’s correlation analysis to examine the links between these variables and primary tumor stage and grading.ResultsHigher PNET grading was associated with higher FSUVmax, MTV, and TLG values (P < 0.05). TLG, SRD, ADCmin, and ADCmean values were correlated with N staging, while SRD, MTV, ADCmin, TLG, and ADCmean were associated with M staging. Notably, ADCmin was a negative correlation between FSUVmax (r = − 0.52; P < 0.001), MTV (r = − 0.50; P < 0.001), and TLG (r = − 0.56; P < 0.001).ConclusionsThis study highlights significant correlative relationships between FDG PET-derived parameters and ADCmin. ADCmin may offer utility as a tool for PNET staging and grading in lieu of FDG PET. 68Ga-DOTATATE PET/MR alone may be a sufficient alternative to dual tracer PET/MR when conducting grading and staging of primary PNETs.

18 F-FDG PET/CT parameters for prediction of response to neoadjuvant therapy and prognosis in rectal cancer.

This study aims to investigate the role of F-18 fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) parameters in the prediction of treatment response and the prognosis in locally advanced rectal cancer. We investigated the relationship of 18F-FDG PET/CT parameters [rectal metabolic tumor volume (MTV), rectal total lesion glycolysis (TLG), rectal standard uptake value (SUV) max, rectal highest peak SUV, lymph node MTV, lymph node TLG, lymph node highest peak SUV] with the pathological response and disease-free survival (DFS) in 60 patients who received neoadjuvant therapy for a diagnosis of locally advanced rectal cancer. Patients with a total score of 0 were assigned to the low-risk group, patients with a score of 1 were assigned to the intermediate-risk group and patients with a score of 2 were assigned to the high-risk group. The multivariate analysis revealed that, from baseline PET CT parameters, lymph node highest peak SUV strongly predicted the pathological response at a cutoff value of 2.23. DFS was predicted by the lymph node highest peak SUV at a cutoff value of 3.13 and by the MTV value at a cutoff value of 27 cm 3 . The risk scoring performed with regard to rectal MTV and lymph node highest peak SUV values determined a median DFS of 19 months in patients with a risk score of 2, whereas the median DFS was not reached in patients with risk scores of 0 and 1 (P < 0.001). This study determined that rectal MTV and lymph node highest peak SUV predicted the response to neoadjuvant therapy and DFS.

Metabolic Tumor Volume Predicts Outcomes in Patients with Relapsed/Refractory Diffuse Large B-Cell Lymphoma Treated with Loncastuximab Tesirine in the Lotis-2 Trial

Introduction: Identification of new predictive biomarkers in relapsed/refractory (rel/ref) diffuse large B-cell lymphoma (DLBCL) is essential for individualized treatment selection and optimization of outcomes. Metabolic tumor volume (MTV) is a strong prognostic factor in DLBCL, though, its value in patients treated with loncastuximab tesirine has not yet been explored. We investigated the impact of quantitative PET/CT data on treatment response and survival in patients treated with this compound. Methods: In this post-hoc analysis, we reviewed screening PET/CT images of patients enrolled in the LOTIS-2 trial (NCT03589469). MTV was obtained by adding the metabolic volumes of all individual lesions using the 41% of SUVmax threshold. Total lesion glycolysis (TLG) was calculated as the product of MTV and SUVmean for all individual lesions. SUVmax, MTV and TLG were calculated on screening PET/CT images by a nuclear medicine (NM) radiologist using Hermes Affinity Viewer software. Values calculated by the first reader were independently confirmed by a second NM reader and a deep learning-aided automated method (Kuker R, et al. SNMMI 2022). We tested if these quantitative metrics presented as continuous variables, in the original scale and as log2-transformed data, could predict treatment response, event-free survival (EFS) and overall survival (OS). We also used an outcome-oriented method to determine cutpoints (c) as markers for risk-stratification. Internal validation based on bootstrap was performed to evaluate predictive performance of identified cutpoints. Optimism was calculated using mean of differences between AUC of bootstrap sample and AUC of original dataset. The optimism-corrected AUCs (ocAUC) was considered to take account of model overfitting. The goals of this study were to assess the impact of quantitative PET/CT metrics to predict complete metabolic response (CMR) (primary endpoint) and survival (secondary endpoints) after loncastuximab tesirine treatment. We grouped together patients with no metabolic response (NMR), disease progression (PD), and not evaluable (NE) due to similar survival. Results: At the time of analysis, PET/CT images were available for review in 118 of the 145 patients enrolled. We first investigated the predictive value of PET/CT metrics to determine CMR. Patients achieving CMR exhibited significantly lower values in SUVmax, MTV and TLG (Table 1). We identified high interobserver agreement in MTV values. As continuous variables, log2(SUVmax), log2(MTV) and log2(TLG) were predictive of failure to achieve CMR (1-unit increase odds ratio [OR]= 1.06, 95%CI 1.01-1.10, P=0.008, AUC=0.666; OR=1.52, 95%CI 1.22-1.89, P=0.002, AUC=0.744; and OR=1.49, 95%CI 1.23-1.80, P<.0001, AUC=0.758; respectively). We identified the cutpoints of SUVmax ≥17 (OR=3.94, 95%CI 1.62-9.58, P=0.002, ocAUC= 0.653), MTV ≥43ml (OR=6.82, 95%CI 2.51-18.51, P=0.0002, ocAUC=0.716) and TLG ≥434 (OR=6.84, 95%CI=2.61-17.89, P<.001, ocAUC=0.720) as predictors of failure to achieve CMR. Next, we assessed the association of PET/CT metrics with EFS and OS. Median EFS & OS (months) by treatment response were: CMR= not reached (NR) (95%CI 14.2-NR) & NR (95%CI 16.2-NR); PMR= 3.4 (95%CI 2.8-7.4) & 11.2 (95%CI 7.1-16.4); NMR/PD= 1.4 (95%CI 1.3-2) & 5.8 (95%CI 2.6-6.9); (P<.0001) respectively. Again, log2(MTV) (hazard ratio (HR)=1.28, 95%CI 1.15-1.42, P<.0001 and HR=1.38, 95%CI 1.22-1.55, P<.0001) and log2(TLG) (HR=1.21, 95%CI 1.11-1.32, P<.0001 and HR=1.29, 95%CI 1.17-1.42, P<.0001) predicted shorter EFS and OS, respectively. log2(SUVmax) predicted only shorter OS (HR=1.02, 95%CI 1.00-1.03, P=0.033). We observed SUVmax ≥18 (EFS: HR=1.65, 95%CI 1.06-2.55, P=0.027 & OS: HR=1.7, 95%CI 1.06-2.75, P=0.029), MTV ≥68ml (EFS: HR=3.02, 95%CI 1.94-4.7, P<.0001 & OS: HR=3.26, 95%CI 2.05-5.19, P<.0001) and TLG ≥479 (EFS: HR=2.34, 95%CI 1.52-3.6, P=.0001 & OS: HR=2.46, 95%CI 1.54-3.91, P=.0001) as cutpoints associated with shorter survival. Conclusion: In the present analysis we demonstrated the predictive impact of PET/CT data in rel/ref DLBCL retaining its risk-stratification power as continuous and categorical variables. MTV is an imaging biomarker extracted from routine PET/CT scans and enables individualized treatment selection identifying those patients that will benefit the most from loncastuximab tesirine. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

High Metabolic Tumor Volume Is Associated with Higher Toxicity and Decreased Efficacy of BCMA CAR-T Cell Therapy in Multiple Myeloma

Background Recently, two chimeric antigen receptor T-cell (CAR-T) constructs have been FDA approved for relapsed/refractory multiple myeloma (RRMM) after exposure to at least 4 prior lines of therapy. High tumor burden has been associated with inferior outcomes, reduced CAR-T expansion and higher rates of toxicity. Patients relapsing after multiple lines of therapy more frequently have oligosecretory and extra-medullary disease that may not be well captured by serum-based markers of disease or bone marrow infiltration, respectively. Functional imaging with FDG-PET is well established as a useful tool in patients with myeloma but its prognostic impact in highly refractory patients or those proceeding with CAR-T has not been described. Metabolic tumor volume (MTV) capturing all metabolically active disease can be useful as a more global assessment of disease burden. We sought to evaluate tumor burden as measured by MTV in a cohort of patients presenting for anti-BCMA CAR-T with RRMM. Methods We identified all patients presenting to our center treated with anti-BCMA CAR-T with available restaging imaging performed within 60 days prior to lymphodepleting chemotherapy (LD-chemo). Baseline skull to midthigh with or without leg/whole-body 18F-FDG PET/CT scans were evaluated for MTV using a custom tool implemented on MIM PACS version 7.1 (MIM Software, Cleveland, OH) as previously reported (Dean et al, Blood Adv 2020). Briefly, images were semi-automatically analyzed to identify abnormal regions with reference to average metabolic activity of normal liver defined by PET SUV. Metabolically active volume at the lesion level were converged based on PERCIST criteria (41% of SUVmax). Summation of the metabolically active volumes across the human body is reported as the Metabolically Tumor Volume (MTV), measured in ml. Patient image scans were reviewed centrally by a radiologist blinded to outcomes, who removed any false positive uptake unrelated to metabolically active disease. Patients with the following FISH cytogenetics were considered high risk (HR): t(4;14), t(14;16) and deletion 17p/monosomy 17 whereas the remainder were standard risk (SR). The high and low tumor volume groups were selected based on the median MTV value in cohort. Baseline laboratory tests (e.g. beta2 microglobulin (b2M), C-reactive protein (CRP)) and repeat bone marrow biopsy were obtained prior to LD-chemo. Soluble BCMA (sBCMA) was measured by ELISA on patients with available serum samples (R&D Systems, MN, USA #DY193). All analyses were conducted in Stata (16.1, StataCorp LLC, College Station, TX). Results The study cohort consisted of 66 patients. Median age was 65 years (range 36 - 81), 55% were male, 55% had ECOG 0-1 prior to LD-chemo and 65% received bridging therapy. 25 (38%) were categorized as HR based on FISH cytogenetics. Patients had received a median of 6 prior lines of therapy and median interval between PET and date of CART infusion was 14.5 days (range 2-54). Median MTV was 26.3ml (0.26-1073.87ml) and only 3/66 (5%) had no measurable PET-avid lesions captured by this algorithm. Patients with high MTV (>26) were more likely to have elevated baseline CRP >0.5mg/dL (p=0.007) and receive bridging therapy (60% vs 40%, p=0.02). MTV correlated with sBCMA levels on day -6 (r=0.82, p=0.003), and with baseline b2M (r=0.47, p=0.005), but MTV did not correlate well with percentage plasma cells in pre-CAR-T bone marrow biopsy (r=0.12, p=0.3). The risk of ³G2 CRS was significantly higher (44% vs 12%, p=0.02) and any grade ICANS was numerically higher (27% vs 12%, p=0.1) in those with high vs low MTV, respectively. Finally, fewer patients with high MTV achieved CR by D30 (19% vs 31%, p=0.2) and with limited follow up 12/14 (86%) of deaths had occurred in patients with high baseline MTV (p=0.003). Conclusion These preliminary data confirm the added value of MTV calculated from baseline imaging as part of standard of care in patients with heavily pre-treated relapsed myeloma presenting for anti-BCMA CAR-T therapy. MTV correlated highly with sBCMA measured at day-6 and may be more representative for risk assessment than basing burden on bone marrow plasma cell percentage, which has not demonstrated a consistent relationship in predicting adverse events to date. High MTV appears to be associated with an increased risk of CAR-T specific adverse events and inferior outcomes and warrants further investigation. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Immune Signature of Pembrolizumab Plus Gemcitabine, Vinorelbine, and Liposomal Doxorubicin As Second-Line Therapy for Relapsed or Refractory Classical Hodgkin Lymphoma

Introduction: In our phase II study (Moskowitz AJ et al, JCO 2021), pembrolizumab plus gemcitabine, vinorelbine, and liposomal doxorubicin (P-GVD) was found to be highly effective as salvage for patients (pts) with relapsed or refractory (R/R) classic Hodgkin lymphoma (cHL) proceeding to high dose therapy and autologous hematopoietic cell transplantation (AHCT). We present analyses assessing immunologic changes associated with P-GVD treatment as well as updated clinical outcome. Methods: Transplant eligible pts with R/R cHL following failure of 1-line of therapy were eligible. Treatment consisted of 2 to 4 cycles of P-GVD followed by AHCT. Peripheral blood samples were collected at baseline, after 2 cycles of P-GVD, before AHCT, 3 and 9 months after AHCT. Peripheral blood was analyzed for serum thymus and activation-regulated chemokine (TARC) and immune cell subsets. TARC was measured by enzyme-linked immunosorbent assay. Immune cell subsets, including T-cells and myeloid-derived suppressor cells (MDSC), were measured by multi-parametric flow cytometry (FC). Metabolic tumor volume (MTV) was evaluated at baseline. Changes in MDSC and TARC levels were assessed using Wilcoxon rank sum and Friedman tests, respectively. Correlations between MTV and either TARC or MDSC were assessed using Pearson's R. Results: Of 38 evaluable pts, the complete response (CR) rate after 2 or 4 cycles of P-GVD was 95%. Two pts declined AHCT and 36 proceeded to AHCT. After a median follow-up of 30 months (range: 2-43), only 1 pt experienced disease progression 23 months after AHCT. The estimated 30-month progression-free survival (PFS) is 96%. The median baseline MTV value was 37 cm3 (range 4- 845). 36/38 and 27/38 pts had sufficient correlative samples to perform analysis for TARC and MDSC analysis, respectively. The median baseline TARC level was 526 pg/mL (range: 12-4017). TARC levels decreased significantly after 2 cycles of P-GVD (p < 0.001) and increased post-AHCT. Circulating MDSCs were 0.05% of total mononuclear cells (range: 0.003-0.59%) and significantly increased after 2 cycles of P-GVD (p<0.001). Higher baseline TARC and circulating MDSC levels correlated with higher baseline MTV (r=0.45, 95% CI: 0.11-0.70, p<0.01 and r=0.46, 95%CI 0.03-0.76, p=0.03, respectively). High-dimensional analysis of FC data revealed several distinct immune clusters (Figure 1), of which non-proliferating PD-1+ CD4+ T-cells decreased most significantly following treatment (Figure 2). Additional markers (ICOS, CTLA-4, LAG-3, FOXP3) of immune exhaustion showed only a mild decrease over the treatment course. Conclusions: After a median of 30-months follow-up, second-line P-GVD continues to be associated with durable remissions after AHCT. These analyses provide insights into key immune changes associated with chemoimmunotherapy in HL. Baseline TARC correlated with baseline MTV and was significantly lower after P-GVD, illustrating its role as a marker of tumor bulk. The subsequent rise in serum TARC post AHCT suggests immune reconstitution of TARC-secreting cells. Higher circulating levels of MDSCs correlated with baseline MTV, which may reflect an association between immune suppression and tumor bulk. MDSC levels unexpectedly increased after P-GVD, indicating that a rise in MDSCs after treatment may not necessarily predict for poor outcomes. Ongoing single-cell RNA sequencing analysis of peripheral blood mononuclear cells (PBMC) may provide further understanding into immune dynamics associated with P-GVD treatment. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal