Primary clear cell renal cell carcinoma (ccRCC) genetic heterogeneity may lead to an underestimation of the mutational burden detected from a single site evaluation. We sought to characterize the extent of clonal branching involving key tumor suppressor mutations in primary ccRCC and determine if genetic heterogeneity could limit the mutation profiling from a single region assessment. Ex vivo core needle biopsies were obtained from three to five different regions of resected renal tumors at a single institution from 2012 to 2013. DNA was extracted and targeted sequencing was performed on five genes associated with ccRCC (von‐Hippel Lindau [VHL], PBRM1, SETD2, BAP1, and KDM5C). We constructed phylogenetic trees by inferring clonal evolution based on the mutations present within each core and estimated the predictive power of detecting a mutation for each successive tumor region sampled. We obtained 47 ex vivo biopsy cores from 14 primary ccRCC's (median tumor size 4.5 cm, IQR 4.0–5.9 cm). Branching patterns of various complexities were observed in tumors with three or more mutations. A VHL mutation was detected in nine tumors (64%), each time being present ubiquitously throughout the tumor. Other genes had various degrees of regional mutational variation. Based on the mutations' prevalence we estimated that three different tumor regions should be sampled to detect mutations in PBRM1, SETD2, BAP1, and/or KDM5C with 90% certainty. The mutational burden of renal tumors varies by region sampled. Single site assessment of key tumor suppressor mutations in primary ccRCC may not adequately capture the genetic predictors of tumor behavior.

Study Type – Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Outcomes after disease recurrence in patients with urothelial carcinoma of the bladder treated with radical cystectomy are variable, but the majority of patients die from the disease within 2 years after disease recurrence. Knowledge about prognostic factors that may influence survival after disease recurrence is limited. We found that outcomes after disease recurrence in patients with urothelial carcinoma of the bladder are significantly affected by common clinicopathological factors. In addition, a shorter time from surgery to disease recurrence is significantly associated with poor outcomes. These factors should be considered when scheduling salvage chemotherapy protocols/clinical trials. OBJECTIVE: To describe the natural history following disease recurrence after radical cystectomy (RC) and to identify prognostic factors that influence cancer‐specific survival with special focus on time from RC to disease recurrence. METHODS: We identified 1545 patients from 16 international institutions who experienced disease recurrence after RC and bilateral lymphadenectomy. None of the patients received preoperative chemotherapy; 549 patients received adjuvant chemotherapy. A multivariable Cox regression model addressed time to cancer‐specific mortality after disease recurrence. RESULTS: The median cancer‐specific survival time after disease recurrence was 6.9 months (95% CI 6.3–7.4). Overall, 1254 of 1545 patients died from urothelial carcinoma of the bladder and 47 patients died from other causes. The actuarial cancer‐specific survival estimate at 12 months after disease recurrence was 32%. On multivariable analysis, non‐organ‐confined tumour stages (hazard ratio [HR] 1.38, P = 0.002), lymph node metastasis (HR 1.25, P < 0.001), positive soft tissue surgical margin (HR 1.32, P = 0.002), female gender (HR 1.21, P = 0.003), advanced age (HR 1.16, P < 0.001) and a shorter interval from surgery to disease recurrence ( P < 0.001) were significantly associated with cancer‐specific mortality. The adjusted risk of death from cancer within 1 year after disease recurrence for patients who recurred 6, 12 and 24 months after surgery was 70%, 64% and 60%, respectively. CONCLUSIONS: Over two‐thirds of patients who experience disease recurrence of urothelial carcinoma of the bladder after RC die within 12 months. Common clinicopathological factors are strongly associated with cancer‐specific mortality. A shorter time from surgery to disease recurrence is significantly associated with poor outcomes. Accurate risk stratification could help in patient counselling and decision‐making regarding salvage treatment.

Tumor size and stage are important prognostic parameters in renal cell carcinoma. While pathological stage T1 and T2 are defined by size alone, the presence of certain intrinsic features can up stage a tumor to pathological stage T3a regardless of size. We investigate the effect of pathological tumor stage on the relationship between tumor size and risk of disease recurrence. Data were reviewed on patients who underwent nephrectomy at our institution between 2006 and 2013 to identify all those with pathological stage T1, T2 and T3a tumors. A proportional hazards Cox model was built with time to recurrence as outcome, and pathological stage and tumor size as covariates. An interaction term for stage and tumor size was included. The final cohort included 1,809 patients. On multivariable analysis, when adjusted for tumor size, patients with pT3a tumors had a greater risk of tumor recurrence compared to those with pT1/T2 tumors (HR 3.70; 95% CI 2.31, 5.92; p <0.0001). The risk of disease recurrence increased more rapidly as tumor size increased only with the presence of perinephric fat invasion (p=0.006). Using the AJCC 2010 staging criteria we validated pathological stage T3a as a poor prognostic factor in renal cell carcinoma regardless of tumor size. Our results also demonstrated an increased rate of risk of recurrence with perinephric fat invasion. Given this increased risk of recurrence, even in tumors less than 4 cm, closer surveillance is warranted in such cases and the role of perinephric involvement necessitates further investigation.