Thompson, R. Houston

672 Background: The optimal sequence of cytoreductive nephrectomy (CN) and targeted therapy (TT) for patients with metastatic renal cell carcinoma (mRCC) remains to be established. Herein, we compared overall survival (OS) between patients with mRCC receiving initial CN with or without subsequent TT versus initial TT with or without subsequent CN. Methods: The National Cancer Database (NCDB) was used to identify patients diagnosed between 2006-2013 with RCC that was metastatic at diagnosis who received CN, TT, or both. Those with other prior cancer history were excluded. The cumulative incidence of receiving TT after CN and CN after TT were evaluated, with death prior to second treatment as a competing risk. To account for treatment selection bias, inverse probability of treatment weighting (IPTW) was performed based on the propensity to receive initial CN or TT. OS from diagnosis was compared using Cox regression. Sensitivity analyses were performed. Results: The cohort included 15,068 patients, of whom 6,731 underwent initial CN and 8,337 underwent initial TT. At 6 months from diagnosis, the probability of receiving TT after CN was 46.2%, with 13.6% of patients having died after initial CN prior to receiving TT. Meanwhile, the probability at 6 months of undergoing CN after initial TT was 4.4%, with 38.3% of this group having died prior to undergoing CN. In the IPTW analysis, baseline characteristics were balanced (standardized difference < 0.1). Initial CN was associated with improved OS compared to initial TT (median 16.5 vs 9.2 months; HR 0.62; 95%CI 0.61-0.64; p < 0.001). Findings were similar in all sensitivity analyses (propensity score matching and adjustment; regression adjustment; 6-month landmark analysis; clear cell mRCC subset; exclusion of patients who had metastasectomy). Conclusions: Although initial CN was associated improved OS versus initial TT in this national dataset, initial CN was associated with delays in, and even death prior to, receipt of TT. As such, while the survival data here support initial CN in appropriate surgical candidates, continued efforts to develop the optimal multimodal approach to these patients are warranted.

Our objective was to evaluate the role of retroperitoneal lymph node dissection ( LND ) in non‐metastatic (M0) and metastatic (M1) renal cell carcinoma ( RCC ). We searched Medline, EMBASE , Web of Science and Scopus from database inception to 29 August 2017 for studies of patients who underwent partial or radical nephrectomy for M0 or M1 RCC . Two investigators independently selected studies for inclusion. Risk of bias was assessed using the Newcastle–Ottawa scale, Cochrane Collaboration tool and National Heart, Lung and Blood Institute Quality Assessment Tool. Random effects meta‐analysis was performed for all‐cause‐mortality. The GRADE approach was used to characterize quality of evidence. A total of 51 unique studies were included in the qualitative systematic review. Risk of bias was low in 41/51 (80%) studies. LND was not associated with all‐cause mortality in either M0 (hazard ratio [ HR ] 1.02, 95% confidence interval [ CI ] 0.92–1.12; I 2 = 0%; four studies), M1 ( HR 1.04, 95% CI 0.83–1.29; I 2 = 0%; two studies), or pooled M0 and M1 settings ( HR 1.00, 95% CI 0.92–1.09; I 2 = 0%; seven studies), with no statistically significant differences according to M stage subgroups ( P = 0.50). In the three studies that examined M0 subgroups with a high risk of nodal metastasis, LND was not associated with improved oncological outcomes. Studies on the association of extent of LND with survival reported inconsistent results. Meanwhile, a small proportion of patients with pN 1M0 disease demonstrate durable long‐term oncological control after surgery, with 10‐year cancer‐specific survival of 21–31%. Nodal involvement is independently associated with adverse prognosis in both M0 and M1 settings. GRADE quality of evidence was moderate or low for the outcomes examined. Although LND yields independent prognostic information, the existing literature does not support a therapeutic benefit to LND in either M0 or M1 RCC . High‐risk M0 patient groups warrant further study, as a subset of patients with isolated nodal metastases experience long‐term survival after surgical resection.

Purpose Enhancer of zeste homolog 2 (EZH2), a chromatin remodeler, is implicated in the pathogenesis of clear cell renal cell carcinoma (ccRCC). However, the effect of EZH2 on outcomes in localized ccRCC is unclear, and molecular biomarkers are not currently integrated into prognostic models or adjuvant therapy trials. Methods We performed Cox regression to evaluate the association of tumor-based EZH2 gene and protein expression with survival in three independent cohorts: a cohort from The Cancer Genome Atlas (n = 532), a cohort from University of Texas Southwestern Medical Center (n = 122), and a cohort from Mayo Clinic (n = 1,338). Analyses were adjusted for the prognostic stage, size, grade, and necrosis (SSIGN) score as well as within low-, intermediate-, and high-risk SSIGN groups. Results Patients in The Cancer Genome Atlas cohort with EZH2-high gene expression were 1.5 times more likely to experience overall death than patients with EZH2-low expression (95% CI, 1.1 to 2.3; P = .028). Patients in the University of Texas Southwestern Medical Center cohort with EZH2-high protein expression were two times more likely to experience overall death than patients with EZH2-low expression (95% CI, 1.1 to 4.4; P = .034). Similarly, patients in the Mayo Clinic cohort with EZH2-high protein expression were 1.4 times more likely to experience overall death (95% CI, 1.2 to 1.7; P < .001). Patients in the Mayo Clinic cohort with EZH2-high protein expression were nearly two times more likely to experience RCC-specific death (95% CI, 1.5 to 2.6; P < .001); EZH2 protein expression was particularly prognostic among patients with low-risk SSIGN tumors (HR, 6.1; 95% CI, 3.4 to 11.1; P < .001). Conclusion EZH2 expression accurately predicts risk of RCC death beyond existing clinicopathologic models, particularly in low- and intermediate-risk SSIGN tumors. Further studies are required to incorporate molecular biomarkers into surveillance guidelines and adjuvant clinical trials.

Chromophobe renal cell carcinoma (chRCC) typically shows ~7 chromosome losses (1, 2, 6, 10, 13, 17, and 21) and ~31 exonic somatic mutations, yet carries ~5%–10% metastatic incidence. Since extensive chromosomal losses can generate proteotoxic stress and compromise cellular proliferation, it is intriguing how chRCC, a tumor with extensive chromosome losses and a low number of somatic mutations, can develop lethal metastases. Genomic features distinguishing metastatic from nonmetastatic chRCC are unknown. An integrated approach, including whole-genome sequencing (WGS), targeted ultradeep cancer gene sequencing, and chromosome analyses (FACETS, OncoScan, and FISH), was performed on 79 chRCC patients including 38 metastatic (M-chRCC) cases. We demonstrate that TP53 mutations (58%), PTEN mutations (24%), and imbalanced chromosome duplication (ICD, duplication of ≥ 3 chromosomes) (25%) were enriched in M-chRCC. Reconstruction of the subclonal composition of paired primary-metastatic chRCC tumors supports the role of TP53 , PTEN , and ICD in metastatic evolution. Finally, the presence of these 3 genomic features in primary tumors of both The Cancer Genome Atlas kidney chromophobe (KICH) ( n = 64) and M-chRCC ( n = 35) cohorts was associated with worse survival. In summary, our study provides genomic insights into the metastatic progression of chRCC and identifies TP53 mutations, PTEN mutations, and ICD as high-risk features.

Objectives To compare renal functional changes after percutaneous cryoablation ( PCA ) or partial nephrectomy ( PN ). Patients and Methods Patients who underwent PCA or PN for a solitary renal mass at a single institution were identified (2003–2013). Estimated glomerular filtration rates ( eGFR s) were calculated at baseline, discharge, and at the 3‐month follow‐up using the Chronic Kidney Disease Epidemiology Collaboration equation. Changes in renal function were compared between groups using 1:1 propensity score ( PS ) matching, adjustment for PS quintile, and inverse probability weighting ( IPW ). Results There were 2 040 procedures available for the PS analyses, including 448 PCA and 1 592 PN . After PS adjustments, there were no significant differences in baseline clinical features between PCA and PN patients. In the PS ‐matched analysis, the change in eGFR from baseline to discharge for PCA and PN patients was −3.1 and −1.1 mL /min/1.73 m 2 , respectively ( P = 0.038), with percentage changes of −4.5% and 0% respectively ( P = 0.006). From baseline to the 3‐month follow‐up, the absolute change in eGFR for PCA and PN patients was −4.3 and −2.1 mL /min/1.73 m 2 , respectively ( P = 0.008), and the percentage change was −6.1% and −2.4% respectively ( P = 0.005). Similar results were obtained after adjusting for PS quintiles and in the IPW analysis. Importantly, the rate of chronic kidney disease stage progression at the 3‐month follow‐up was similar between the groups (21% vs 18%). Conclusions Our results confirm that both PCA and PN have a minor impact on renal function. While we observed a statistically greater decline in eGFR after PCA compared with PN , both approaches result in excellent preservation of renal function.