Primary Renal Cell Carcinoma Research Articles

P191 Stereotactic Body Radiotherapy (SBRT) for the treatment of primary localized renal cell carcinoma: A systematic review and meta-analysis

P191 Stereotactic Body Radiotherapy (SBRT) for the treatment of primary localized renal cell carcinoma: A systematic review and meta-analysis

Stereotactic Body Radiotherapy (SBRT) for the Treatment of Primary Localized Renal Cell Carcinoma: A Systematic Review and Meta-Analysis

Context: Surgery is the gold standard for the local treatment of primary renal cell carcinoma (RCC), but alternatives are emerging. We conducted a systematic review and meta-analysis to assess the results of prospective studies using definitive stereotactic body radiotherapy (SBRT) to treat primary localised RCC. Evidence acquisition: This review was prospectively registered in PROSPERO (CRD42023447274). We searched PubMed, Embase, Scopus, and Google Scholar for reports of prospective studies published since 2003, describing the outcomes of SBRT for localised RCC. Meta-analyses were performed for local control (LC), overall survival (OS), and rates of adverse events (AEs) using generalised linear mixed models (GLMMs). Outcomes were presented as rates with corresponding 95% confidence intervals (95% CIs). Risk-of-bias was assessed using the ROBINS-I tool. Evidence synthesis: Of the 2983 records, 13 prospective studies (n = 308) were included in the meta-analysis. The median diameter of the irradiated tumours ranged between 1.9 and 5.5 cm in individual studies. Grade ≥ 3 AEs were reported in 15 patients, and their estimated rate was 0.03 (95%CI: 0.01–0.11; n = 291). One- and two-year LC rates were 0.98 (95%CI: 0.95–0.99; n = 293) and 0.97 (95%CI: 0.93–0.99; n = 253), while one- and two-year OS rates were 0.95 (95%CI: 0.88–0.98; n = 294) and 0.86 (95%CI: 0.77–0.91; n = 224). There was no statistically significant heterogeneity, and the estimations were consistent after excluding studies at a high risk of bias in a sensitivity analysis. Major limitations include a relatively short follow-up, inhomogeneous reporting of renal function deterioration, and a lack of prospective comparative evidence. Conclusions: The short-term results suggest that SBRT is a valuable treatment method for selected inoperable patients (or those who refuse surgery) with localised RCC associated with low rates of high-grade AEs and excellent LC. However, until the long-term data from randomised controlled trials are available, surgical management remains a standard of care in operable patients.

Impact of tumor multiplicity on the prognosis of patients with primary renal cell carcinoma: a SEER database analysis

To compare clinical characteristics and survival outcomes of patients with multiple renal cell carcinoma versus single renal cell carcinoma. Develop a prognostic model for predicting prognosis in patients with multiple tumors and analyze prognostic factors. Patients with primary multiple renal cell carcinoma were selected from the Surveillance, Epidemiology, and End Results database (2004–2015). They were divided into single-tumor and multiple-tumor groups. Survival analysis was conducted using the Kaplan–Meier method and log-rank test. A Cox regression model was used to identify potential prognostic factors. A total of 19,489 renal cell carcinoma cases were included, with 947 in the multiple-tumor group and 18,542 in the single-tumor group. The multiple-tumor group had lower cancer-specific survival (P = 0.03, HR = 1.431). Cox regression identified risk factors for the multiple-tumor group including number of tumors, gender, combined summary stage, T stage, N stage, tumor size, and type of surgery. The predicted probabilities showed acceptable agreement with the actual observations at 3-, 5-, and 8-years area under the curve values in both the training and validation cohorts (0.831 vs. 0.605; 0.775 vs. 0.672; and 0.797 vs. 0.699, respectively). Compared with single renal cell carcinoma, multiple renal cell carcinoma is associated with decreased cancer-specific survival. Additionally, we identified several prognostic factors including the number of tumors, T stage, tumor size, and type of surgery. These findings offer valuable insights for selecting appropriate treatment strategies for patients diagnosed with multiple renal cell carcinomas.

Comparative analysis of dual immune checkpoint inhibitor combination therapy versus immune checkpoint inhibitor plus tyrosine kinase inhibitor combination therapy for renal cell carcinoma with inferior vena cava tumor thrombosis.

Whether immune checkpoint inhibitor (ICI) plus ICI combination therapy or ICI plus tyrosine kinase inhibitor (TKI) combination therapy is useful for renal cell carcinoma (RCC) with inferior vena cava tumor thrombosis (IVCTT) remains unclear. We retrospectively evaluated the therapeutic effects and incidence of treatment-related adverse events (TRAEs) associated with ICI-based combination therapy in 36 patients with advanced RCC with IVCTT. The median age at initiation of treatment was 71years; the IVCTT stages were cT3b in 22 patients and cT3c in 14. The ICI-ICI and ICI-TKI groups comprised 15 and 21 patients, respectively. Median tumor shrinkage at the best response showed that the primary tumor diameter decreased by 1.8cm (22%), and the IVCTT height decreased by 1.5cm (26%). A higher proportion of patients in the ICI-TKI group experienced tumor shrinkage than those in the ICI-ICI group (primary tumor, p = 0.0325; IVCTT, p = 0.0112). Approximately 27% of patients experienced an increase in the IVCTT height with ICI-ICI combination therapy. No significant difference was observed in the relative tumor shrinkage of IVCTT, primary or level-down staging of IVCTT, other treatment effects, incidence of TRAEs, surgical outcomes, or prognosis between the groups. ICI-based combination therapy is effective against IVCTT and primary RCC. Although ICI-ICI is associated with a higher probability of tumor growth compared with ICI-TKI in the frequency of tumor regression, both therapies may be almost equally effective against primary RCC with IVCTT.

TIGIT expression in renal cell carcinoma infiltrating T cells is variable and inversely correlated with PD-1 and LAG3

PurposeImmune checkpoint inhibitors have revolutionized the treatment of renal cell carcinoma (RCC), but many patients do not respond to therapy and the majority develop resistant disease over time. Thus, there is increasing need for alternative immunomodulating agents. The co-inhibitory molecule T-cell immunoglobulin and ITIM domain (TIGIT) may play a role in resistance to approved immune checkpoint inhibitors and is being investigated as a potential therapeutic target. The purpose of this study was to quantify TIGIT positivity in tumor-infiltrating T cells in RCC.MethodsWe employed tissue microarrays containing specimens from primary RCC tumors, adjacent normal renal tissue, and RCC metastases to quantify TIGIT within tumor-infiltrating CD3+ T cells using quantitative immunofluorescent analysis. We also compared these results to TIGIT+ CD3+ levels in four other tumor types (melanoma, non-small cell lung, cervical, and head and neck cancers).ResultsWe did not observe significant differences in TIGIT positivity between primary RCC tumors and patient-matched metastatic samples. We found that the degree of TIGIT positivity in RCC is comparable to that in lung cancer but lower than that in melanoma, cervical, and head and neck cancers. Correlation analysis comparing TIGIT positivity to previously published, patient-matched spatial proteomic data by our group revealed a negative association between TIGIT and the checkpoint proteins PD-1 and LAG3.ConclusionOur findings support careful evaluation of TIGIT expression on T cells in primary or metastatic RCC specimens for patients who may be treated with TIGIT-targeting antibodies, as increased TIGIT positivity might be associated with a greater likelihood of response to therapy.

47 Generation and Characterization of Ex Vivo Expanded Tumor-Infiltrating Lymphocytes from Renal Cell Carcinoma Tumors for Adoptive Cell Therapy

Abstract Background Autologous therapeutic tumor-infiltrating lymphocyte (TIL) therapy is a promising strategy to enhance anti-tumor immunity. Optimization of ex vivo TIL expansion could expand current immunotherapy options. Previous attempts to generate TIL in renal cell carcinoma (RCC) have been technically challenging. We applied a second-generation manufacturing process, currently used to generate the melanoma TIL product lifileucel, in RCC. Methods Resected primary and metastatic RCC samples were processed using the Gen 2 manufacturing process comprising of pre-Rapid Expansion Protocol (pre-REP) and REP steps. We assessed REP TILs for viability and performed phenotypic and functional characterization. We correlated the tumor immune microenvironment (TIME) with successful TIL expansion. Results Eight of 11 RCC samples underwent successful REP. Three failed cases demonstrated low CD8/FoxP3 ratio and high expression of PD-1 within FoxP3 cells. Expression of exhaustion markers differed between the TIME and expanded TILs; the latter had a TIM3-high/PD-1-low phenotype but retained functional capacity comparable to lifileucel. Figure: Assessment of tumor immune microenvironment (TIME) via multiplex immunofluorescence (IF). Cases that failed REP are indicated in red. (A) Representative image at 60x magnification, fluorophore colors as indicated. (B) Density of tumor-infiltrating CD8+ and FoxP3+ cells. (C) Expression of co-inhibitory exhaustion markers as a percentage of total CD8+ cells. (D) Expression of PD-1 in FoxP3+ cells. (E) Comparison of tissue TIME (dots) with TIL product post-REP (open circles) exhaustion profiles as a percentage of total CD8+ cells. Conclusions The Gen 2 manufacturing process used for lifileucel successfully expanded functional TILs from RCC samples, enabling further study in a clinical trial. TIME features such as low CD8/FoxP3 ratio and high PD-1 expression within FoxP3 cells warrant study as potential biomarkers of successful TIL expansion.

Stereotactic Body Radiotherapy: is less fractionation more effective in adrenal and renal malignant lesions?

PurposeStereotactic body radiotherapy (SBRT) has become an excellent non-invasive alternative for many patients with primary renal cell carcinoma (RCC) and adrenal malignancies (AM). The aims of this study were to analyse how tumor-, patient- and treatment-related factors may influence the outcomes and side effects of SBRT and to assess its benefits as an alternative to surgery.MethodsThis retrospective, multicenter study included 25 lesions in 23 patients treated with SBRT using different devices (LINAC, CyberKnife® and Tomotherapy®). A multivariate linear regression was used for the statistical study.ResultsLocal control time was higher than six months in more than 87% of patients and treatment response was complete for 73.68%. There was an overall 2-year survival of 40% and none of the deaths were secondary to renal or adrenal local progression. Patients treated with lower total radiation dose (mean [m] = 55 Gy) but less fractions with more dose per fraction (> 8.5 Gy) showed better outcome. Patients with previous chemotherapy and surgery treatments also showed higher complete response and disease-free survival (> 6 months).ConclusionsThis study highlights the importance of ultra-hypofractionated regimens with higher doses per session. Thus, the referral of patients with RCC and AM to Radiotherapy and Oncology departments should be encouraged supporting the role of SBRT as a minimally invasive and outpatient treatment.

Generation and Characterization of Ex Vivo Expanded Tumor-infiltrating Lymphocytes From Renal Cell Carcinoma Tumors for Adoptive Cell Therapy.

Autologous therapeutic tumor-infiltrating lymphocyte (TIL) therapy is a promising strategy to enhance antitumor immunity. Optimization of ex vivo TIL expansion could expand current immunotherapy options. Previous attempts to generate TIL in renal cell carcinoma (RCC) have been technically challenging. We applied a second-generation manufacturing process, currently used to generate the melanoma TIL product lifileucel, in RCC. Resected primary and metastatic RCC samples were processed using the Gen 2 manufacturing process comprising of pre-Rapid Expansion Protocol (pre-REP) and REP steps. We assessed REP TILs for viability and performed phenotypic and functional characterization. We correlated the tumor immune microenvironment (TIME) with successful TIL expansion. Eight of 11 RCC samples underwent successful REP. Three failed cases demonstrated low CD8/FoxP3 ratio and high expression of PD-1 within FoxP3 cells. Expression of exhaustion markers differed between the TIME and expanded TILs; the latter had a TIM3-high/PD-1-low phenotype but retained functional capacity comparable to lifileucel. The Gen 2 manufacturing process used for lifileucel successfully expanded functional TILs from RCC samples, enabling further study in a clinical trial. TIME features such as low CD8/FoxP3 ratio and high PD-1 expression within FoxP3 cells warrant study as potential biomarkers of successful TIL expansion.

Comparison of Primary and Metastatic Fumarate Hydratase-Deficient Renal Cell Carcinomas Documents Morphologic Divergence and Potential Diagnostic Pitfall With Peritoneal Mesothelioma

Fumarate hydratase (FH)-deficient renal cell carcinomas are rare neoplasms characterized by wide morphologic heterogeneity and pathogenetic mutations in the FH gene. They often show aggressive behavior with rapid diffusion to distant organs, so novel therapeutic scenarios have been explored, including EGFR inhibitors and PD-L1 expression for targeted immunotherapy. Herein, we investigated a series of 11 primary FH-deficient renal cell carcinomas and 7 distant metastases to evaluate tumor heterogeneity even in metastatic sites and estimate the specific spread rates to various organs. Furthermore, the tumors were tested for immunohistochemical PD-L1 expression and EGFR mutations. Most metastatic cases involved the abdominal lymph nodes (4/7; 57%), followed by the peritoneum (3/7; 42%), the liver (2/7; 29%), and the lungs (1/7; 14%). Six metastatic localizations were histologically documented, revealing a morphologic heterogeneous architecture often differing from that of the corresponding primary renal tumor. Peritoneal involvement morphologically resembled a benign reactive mesothelial process or primary peritoneal mesothelioma, thus advocating to perform an accurate immunohistochemical panel, including PAX8 and FH, to reach a proper diagnosis. A pure low-grade succinate dehydrogenase–looking primary FH-deficient renal cell carcinoma was also recorded. As for therapy, significant PD-L1 labeling was found in 60% of primary renal tumors, whereas none of them carried pathogenetic EGFR mutations. Our data show that FH-deficient renal cell carcinoma may be morphologically heterogeneous in metastases as well, which involve the lymph nodes, the liver, and the peritoneum more frequently than other renal tumors. Due to the high frequency of this latter (42%), pathologists should always be concerned about ruling out mesothelial-derived mimickers, and the occurrence of rarer, primary, low-grade–looking types. Finally, contrary to EGFR mutations, PD-L1 expression could be a possible predictive biomarker for the therapy of these tumors.

Renal bleeding: imaging and interventions in patients with tumors.

In patients with cancer, spontaneous renal bleeding can stem from a range of underlying factors, necessitating precise diagnostic tools for effective patient management. Benign and malignant renal tumors are among the primary culprits, with angiomyolipomas and renal cell carcinomas being the most common among them. Vascular anomalies, infections, ureteral obstructions, and coagulation disorders can also contribute to renal-related bleeding. Cross-sectional imaging techniques, particularly ultrasound and computed tomography (CT), play pivotal roles in the initial detection of renal bleeding. Magnetic resonance imaging and CT are preferred for follow-up evaluations and aid in detecting underlying enhancing masses. IV contrast-enhanced ultrasound can provide additional information for active bleeding detection and differentiation. This review article explores specific disorders associated with or resembling spontaneous acute renal bleeding in patients with renal tumors; it focuses on the significance of advanced imaging techniques in accurately identifying and characterizing renal bleeding in these individuals. It also provides insights into the clinical presentations, imaging findings, and treatment options for various causes of renal bleeding, aiming to enhance the understanding, diagnosis, and management of the issue.

Immune Phenotype-Genotype Associations in Primary Clear Cell Renal Cell Carcinoma and Matched Metastatic Tissue

Adjuvant immunotherapy has been recently recommended for patients with metastatic clear cell renal cell carcinoma (ccRCC), but there are no tissue biomarkers to predict treatment response in ccRCC. Potential predictive biomarkers are mainly assessed in primary tumor tissue, whereas metastases (METs) remain understudied. To explore potential differences between genomic alterations and immune phenotypes in primary tumors and their matched METs, we analyzed primary tumors (PTs) of 47 ccRCC patients and their matched distant METs by comprehensive targeted parallel sequencing, whole-genome copy number variation analysis, determination of microsatellite instability, and tumor mutational burden. We quantified the spatial distribution of tumor-infiltrating CD8+ T cells and coexpression of the T-cell-exhaustion marker thymocyte selection-associated high mobility group box (TOX) by digital immunoprofiling and quantified tertiary lymphoid structures. Most METs were pathologically “cold.” Inflamed, pathologically “hot” PTs were associated with decreased disease-free survival, worst for patients with high levels of CD8+TOX+ T cells. Interestingly, inflamed METs showed a relative increase in exhausted CD8+TOX+ T cells and increased accumulative size of tertiary lymphoid structures compared with PTs. Integrative analysis of molecular and immune phenotypes revealed BAP1 and CDKN2A/B deficiency to be associated with an inflamed immune phenotype. Our results highlight the distinct spatial distribution and differentiation of CD8+ T cells at metastatic sites, and the association of an inflamed microenvironment with specific genomic alterations.

Stereotactic Body Radiation Therapy for Primary Renal Cell Carcinoma: A Case-Based Radiosurgery Society Practice Guide

Traditionally, renal cell carcinoma (RCC) was considered a radioresistant tumor, thereby limiting definitive radiation therapy management options. However, several recent studies have demonstrated that stereotactic body radiation therapy (SBRT) can achieve high rates of local control for the treatment of primary RCC. In the setting of expanding use of SBRT for primary RCC, it is crucial to provide guidance on practical considerations such as patient selection, fractionation, target delineation, and response assessment. This is particularly important in challenging scenarios where a paucity of evidence exists, such as in patients with a solitary kidney, bulky tumors, or tumor thrombus. The Radiosurgery Society endorses this case-based guide to provide a practical framework for delivering SBRT to primary RCC, exemplified by 3 cases. This article explores topics of tumor size and dose fractionation, impact on renal function and treatment in the setting of a solitary kidney, and radiation's role in the management of inferior vena cava tumor thrombus. Additionally, we review existing evidence and expert opinion on target delineation, advanced techniques such as magnetic resonance imaging guided SBRT, and SBRT response assessment.

Mutational profile of primary clear cell renal cell carcinoma predicts recurrence and potential candidacy for adjuvant immune checkpoint inhibition.

The risk of recurrence after nephrectomy for primary clear cell renal cell carcinoma (ccRCC) is estimated in daily practice solely based on clinical criteria. The aim of this study was to assess the prognostic relevance of common somatic mutations with respect to tumor aggressiveness and outcomes of ccRCC patients after definitive treatment. Primary tumors from 37 patients with ccRCC who underwent radical nephrectomy were analyzed for presence of somatic mutations using a 15-gene targeted next-generation sequencing (NGS) panel. Associations to histopathologic characteristics and outcomes were investigated in the study cohort (n=37) and validated in The Cancer Genome Atlas (TCGA) ccRCC cohort (n=451). VHL was the most frequently mutated gene (51%), followed by PBRM1 (27%), BAP1 (13%), SETD2 (13%), KDM5C (5%), ATM (5%), MTOR (5%), and PTEN (3%). One-third of patients did not have any somatic mutations within the 15-gene panel. The vast majority of tumors harboring no mutations at all or VHL-only mutations (51%) were more frequently of smaller size (pT1-2) and earlier stage (I/II), whereas presence of any other gene mutations in various combinations with or without VHL was enriched in larger (pT3) and higher stage tumors (III) (p=0.02). No recurrences were noted in patients with unmutated tumors or VHL-only mutations as opposed to three relapses in patients with non- VHL somatic mutations (p=0.06). Presence of somatic mutations in PBRM1, BAP1, SETD2, KDM5C, ATM, MTOR, or PTEN genes in 451 TCGA ccRCC patients was associated with a significantly shorter disease-free survival (DFS) compared to those with unaltered tumors (q=0.01). Preliminary findings from this ongoing study support the prognostic value of non- VHL mutations including PBRM1, BAP1, SETD2, KDM5C, ATM, MTOR, and PTEN in primary ccRCC tumors as surrogates of earlier recurrence and potential selection for adjuvant immune checkpoint inhibition.

Deep learning-based pathological prediction of lymph node metastasis for patient with renal cell carcinoma from primary whole slide images

BackgroundMetastasis renal cell carcinoma (RCC) patients have extremely high mortality rate. A predictive model for RCC micrometastasis based on pathomics could be beneficial for clinicians to make treatment decisions.MethodsA total of 895 formalin-fixed and paraffin-embedded whole slide images (WSIs) derived from three cohorts, including Shanghai General Hospital (SGH), Clinical Proteomic Tumor Analysis Consortium (CPTAC) and Cancer Genome Atlas (TCGA) cohorts, and another 588 frozen section WSIs from TCGA dataset were involved in the study. The deep learning-based strategy for predicting lymphatic metastasis was developed based on WSIs through clustering-constrained-attention multiple-instance learning method and verified among the three cohorts. The performance of the model was further verified in frozen-pathological sections. In addition, the model was also tested the prognosis prediction of patients with RCC in multi-source patient cohorts.ResultsThe AUC of the lymphatic metastasis prediction performance was 0.836, 0.865 and 0.812 in TCGA, SGH and CPTAC cohorts, respectively. The performance on frozen section WSIs was with the AUC of 0.801. Patients with high deep learning-based prediction of lymph node metastasis values showed worse prognosis.ConclusionsIn this study, we developed and verified a deep learning-based strategy for predicting lymphatic metastasis from primary RCC WSIs, which could be applied in frozen-pathological sections and act as a prognostic factor for RCC to distinguished patients with worse survival outcomes.

Treatment outcomes of brain metastasis from primary renal cell carcinoma in United States: A National Cancer Database analysis.

4561 Background: The advent of stereotactic radiosurgery (SRS) in treatment of brain metastasis (BM) has improved both clinical outcomes and survival in patients with BM. Recent studies suggest that immunotherapy presents a promising potential in the treatment of patients with BM. However, data regarding the effectiveness of combining SRS with immunotherapy for BM in metastatic renal cell carcinoma (RCC) remain largely unknown. We aim to delineate the impact of various treatment therapies including combination therapy for treatment of RCCBM. Methods: We queried the National Cancer Database (NCDB) to include patients with BM from mRCC from 2004 to 2020. We divided the patients into groups based on the treatment they received. Resultantly, 5 different treatment groups i.e., WRBT± immunotherapy, SRS± immunotherapy and immunotherapy alone were identified. We excluded patients with unknown treatment status. We analyzed survival outcomes using the Kaplan-Meier analysis and compared the effect of treatment modalities on survival with the log-rank test. Results: The NCDB yielded 6,446 patients diagnosed with BM from mRCC. In eligible cases, the median age was 63 years (range: 19-90+ years), 69.2% were male, 86.8% were White, 7.9% were Black, 41.9% had Medicare as primary payor, 27.7% had annual income >$74,063, 79.3% belonged from metropolitan areas, 39.6% were treated at academic/research program, 68.3% had Charlson-Deyo score of 0, 44.6% had an unknown grade of the primary RCC. 1,705 (43.44%) patients who were given WBRT had a median overall survival (OS) of 5.65 months, 427 (10.88%) patients were treated with SRT + immunotherapy had an OS of 19.0 months, 987 (25.15%) patients who underwent SRT only had an OS of 9.7 months, 431 (10.98%) patients who received immunotherapy only showed an OS of 12.9 months, and 375 (9.55%) patients who underwent WBRT + immunotherapy had an OS of 12.78 months (log-rank p <0.001). Conclusions: This national database analysis reveals that the combination of SRS with immunotherapy significantly increases the OS in RCCBM compared to immunotherapy, WBRT, or combination of WRBT and immunotherapy. Further prospective studies are warranted to confirm these findings. [Table: see text]

Stereotactic body radiation therapy for primary renal cell carcinoma: A review on behalf of the CC-AFU

IntroductionThe incidence of localized renal cell carcinoma (RCC) is on the rise among individuals aged 70 and older. While the gold standard for treatment remains surgical resection, some elderly and frail patients with comorbidities are not eligible for this procedure. In selected cases, percutaneous thermal ablation, such as cryotherapy, microwave and radiofrequency, offers less invasive options. General anesthesia is sometimes necessary for such treatments, but most of the procedures can be conducted using mild or deep conscious sedation. This approach is preferably recommended for small cT1a tumors situated at a distance from the renal hilum and/or ureter. Active surveillance remains an alternative in the case of small low grade RCC although it may induce anxiety in certain patients. Recent research has highlighted the potentials of stereotactic ablative body radiotherapy (SABR) as a noninvasive, well-tolerated, and effective treatment for small renal tumors. This narrative review aims to explore recent advances in SABR for localized RCC, including appropriate patient selection, treatment modalities and administration, as well as efficacy and tolerance assessment. Material and methodsWe conducted a literature review using the terms [kidney cancer], [renal cell carcinoma], [stereotactic radiotherapy], [SBRT], and [SABR] in the Medline, PubMed, and Embase databases, focusing on prospective and relevant retrospective studies published in English. ResultsStudies report local control rates ranging from 70% to 100% with SABR, highlighting its efficacy in treating RCC. The decline in glomerular filtration rate (GFR) is approximately −5 to −17mL/min over the years following SABR. Common toxicities are rare, primarily CTCAE grade 1, include fatigue, nausea, chest or back pain, diarrhea, or gastritis. ConclusionStereotactic ablative body radiotherapy (SABR) may be considered as a viable option for patients with localized RCC who are not suitable candidates for surgery with a high local control rate and a favorable safety profile. This approach should be discussed in a multidisciplinary meeting and results from ongoing clinical trials are awaited. Level of evidence5.

Pulmonary lesion after surgery for renal cancer: progression or new primary?

To investigate clinical and radiological differences between kidney metastases to the lung (RCCM +) and metachronous lung cancer (LC) detected during follow-up in patients surgically treated for Renal Cell Carcinoma (RCC). cM0 surgically-treated RCC who harbored a pulmonary mass during follow-up were retrospectively scrutinized. Univariate logistic regression assessed predictive features for differentiating between LC and RCCM + . Multivariable analyses (MVA) were fitted to predict factors that could influence time between detection and histological diagnosis of the pulmonary mass, and how this interval could impact on survivals. 87% had RCCM + and 13% had LC. LC were more likely to have smoking history (75% vs. 29%, p < 0.001) and less aggressive RCC features (cT1-2: 94% vs. 65%, p = 0.01; pT1-2: 88% vs. 41%, p = 0.02; G1-2: 88% vs. 37%, p < 0.001). The median interval between RCC surgery and lung mass detection was longer between LC (55months [32.8-107.2] vs. 20months [9.0-45.0], p = 0.01). RCCM + had a higher likelihood of multiple (3[1-4] vs. 1[1-1], p < 0.001) and bilateral (51% vs. 6%, p = 0.002) pulmonary nodules, whereas LC usually presented with a solitary pulmonary nodule, less than 20mm. Univariate analyses revealed that smoking history (OR:0.79; 95% CI 0.70-0.89; p < 0.001) and interval between RCC surgery and lung mass detection (OR:0.99; 95% CI 0.97-1.00; p = 0.002) predicted a higher risk of LC. Conversely, size (OR:1.02; 95% CI 1.01-1.04; p = 0.003), clinical stage (OR:1.14; 95% CI 1.06-1.23; p < 0.001), pathological stage (OR:1.14; 95% CI 1.07-1.22; p < 0.001), grade (OR:1.15; 95% CI 1.07-1.23; p < 0.001), presence of necrosis (OR:1.17; 95% CI 1.04-1.32; p = 0.01), and lymphovascular invasion (OR:1.18; 95% CI 1.01-1.37; p = 0.03) of primary RCC predicted a higher risk of RCCM + . Furthermore, number (OR:1.08; 95% CI 1.04-1.12; p < 0.001) and bilaterality (OR:1.23; 95% CI 1.09-1.38; p < 0.001) of pulmonary lesions predicted a higher risk of RCCM + . Survival analysis showed a median second PFS of 10.9years (95% CI 3.3-not reached) for LC and a 3.8years (95% CI 3.2-8.4) for RCCM + . The median OS time was 6.5years (95% CI 4.4-not reached) for LC and 6years (95% CI 4.3-11.6) for RCCM + . Smoking history, primary grade and stage of RCC, interval between RCC surgery and lung mass detection, and number of pulmonary lesions appear to be the most valuable predictors for differentiating new primary lung cancer from RCC progression.

Targeting CXCR4 impaired T regulatory function through PTEN in renal cancer patients

BackgroundTregs trafficking is controlled by CXCR4. In Renal Cell Carcinoma (RCC), the effect of the new CXCR4 antagonist, R54, was explored in peripheral blood (PB)-Tregs isolated from primary RCC patients.MethodsPB-Tregs were isolated from 77 RCC patients and 38 healthy donors (HDs). CFSE-T effector-Tregs suppression assay, IL-35, IFN-γ, IL-10, TGF-β1 secretion, and Nrp-1+Tregs frequency were evaluated. Tregs were characterised for CTLA-4, PD-1, CD40L, PTEN, CD25, TGF-β1, FOXP3, DNMT1 transcriptional profile. PTEN-pAKT signalling was evaluated in the presence of R54 and/or triciribine (TCB), an AKT inhibitor. Methylation of TSDR (Treg-Specific-Demethylated-Region) was conducted.ResultsR54 impaired PB-RCC-Tregs function, reduced Nrp-1+Tregs frequency, the release of IL-35, IL-10, and TGF-β1, while increased IFN-γ Teff-secretion. The CXCR4 ligand, CXCL12, recruited CD25+PTEN+Tregs in RCC while R54 significantly reduced it. IL-2/PMA activates Tregs reducing pAKT+Tregs while R54 increases it. The AKT inhibitor, TCB, prevented the increase in pAKT+Tregs R54-mediated. Moreover, R54 significantly reduced FOXP3-TSDR demethylation with DNMT1 and FOXP3 downregulation.ConclusionR54 impairs Tregs function in primary RCC patients targeting PTEN/PI3K/AKT pathway, reducing TSDR demethylation and FOXP3 and DNMT1 expression. Thus, CXCR4 targeting is a strategy to inhibit Tregs activity in the RCC tumour microenvironment.

235: Dose-effect relationship after SABR for primary renal cell carcinoma: FASTRACK II (NCT02613819)

235: Dose-effect relationship after SABR for primary renal cell carcinoma: FASTRACK II (NCT02613819)

Dose-Effect Relationship of Kidney Function After SABR for Primary Renal Cell Carcinoma: TROG 15.03 FASTRACK II

BackgroundStereotactic ablative body radiotherapy (SABR) is a novel option to treat primary renal cell carcinoma (RCC). However, a high radiation dose may be received by the treated kidney, which may affect its function post-treatment. This study investigates the dose-effect relationship of kidney SABR with posttreatment renal function. MethodsThis was a prespecified secondary endpoint of the multicenter FASTRACK II clinical trial (NCT02613819). Patients received either 26 Gy in a single fraction (SF) for tumors with a maximal diameter of 4 cm or less, or 42 Gy in three fractions (multi-fraction (MF)) for larger tumors. To determine renal function change, 99mTc-DMSA SPECT/CT scans were acquired, and the glomerular filtration rate (GFR) was estimated at baseline, 12-, and 24-months post-treatment. Imaging datasets were rigidly registered to the planning CT where kidneys were segmented to calculate dose-response curves. ResultsFrom 71 enrolled patients, data from 36 (51%) and 26 (37%) patients were included in this study based on availability of post-treatment data at 12- and 24-months, respectively. The ipsilateral kidney GFR decreased from baseline by 42% and 39% in the SF cohort, and by 45% and 62% in the MF cohort, at 12- and 24-months respectively (p-values < 0.03). The loss in renal function was 3.6±0.8% and 4.5±1.0% in the SF cohort, and 1.7±0.1% and 1.7±0.2% in the MF cohort, at 12- and 24-months respectively. The major loss in renal function occurred in high-dose regions, where dose-response curves converged to a plateau. ConclusionsFor the first time in a multicenter study, the dose-effect relationship at 12- and 24-months post-SABR treatment for primary RCC was quantified. Kidney function reduces linearly with dose up to 100 Gy BED3.