Faculty Bibliography

INTRODUCTION/BACKGROUND:The benefit of partial nephrectomy (PN) compared to radical nephrectomy (RN) for T1a renal cell carcinoma (RCC) remains uncertain, with observational studies conflicting with level 1 evidence. Therefore, the purpose of this population-based study was to compare long-term outcomes in patients undergoing PN or RN for T1a RCC. METHODS:We studied 5670 patients in Ontario, Canada undergoing PN or RN for T1a RCC. The primary outcome was overall survival (OS). Secondary outcomes were cancer-specific survival (CSS), chronic kidney disease (CKD), renal replacement therapy, and myocardial infarction (MI). We used multivariable Cox proportional hazard models to evaluate the association between PN or RN and these outcomes. A sensitivity analysis was performed in patients with a preoperative serum creatinine available. RESULTS:Median followup was 77 months. Compared to RN, PN was associated with significantly improved OS (hazard ratio [HR] 0.73, 95% confidence interval [CI] 0.63-0.84), reduced risk of CKD (HR 0.18, 95% CI 0.12-0.27), and improved CSS (HR 0.45, 95% CI 0.30-0.65). The risk of MI was not significantly different between groups (HR 0.91, 95% CI 0.62-1.34). Few patients (n=15) required renal replacement therapy. In the sensitivity analysis, the association between type of surgery and OS and CKD persisted, while the association with CSS did not. CONCLUSIONS:Our study found that in patients undergoing surgery for T1a RCC, PN was associated with improved OS and reduced risk of CKD compared to RN. However, few patients in either group required renal replacement therapy.

INTRODUCTION/BACKGROUND:We aimed to study the association of ethnicity on semen parameters and hormones in patients presenting with infertility. METHODS:Data from men presenting for infertility assessment were prospectively collected and retrospectively reviewed. Demographic and clinical history was self-reported. Semen analysis included volume, count, motility, morphology, and vitality. The 2010 World Health Organization cutoffs were used. Baseline total testosterone and follicle-stimulating hormone (FSH) levels were recorded. Ethnicity data was classified as Caucasian, African Canadian, Asian, Indo-Canadian, Native Canadian, Hispanic, and Middle Eastern. All patients with complete data were included and statistical analysis was performed. RESULTS:A total of 9079 patients were reviewed, of which 3956 patients had complete data. Of these, 839 (21.2%) were azoospermic. After adjusting for age, African Canadians (odds ratio [OR] 1.70; 95% confidence interval [CI] 1.28-2.25) and Asians (1.34; 95% CI 1.11-1.62) were more likely to be azoospermic compared to Caucasians. Similarly, African Canadians (OR 1.75; 95% CI 1.33-2.29) were more likely to be oligospermic and Asians (OR 0.82; 95% CI 0.70-0.97) less likely to be oligospermic. Low volume was found in African Canadian (OR 1.42; 95% CI 1.05-1.91), Asians (OR 1.23; 95% CI 1.01-1.51), and Indo-Canadians (OR 1.47; 95% CI 1.01-2.13). Furthermore, Asians (OR 0.73; 95% CI 0.57-0.93) and Hispanics (OR 0.58; 95% CI 034-0.99) were less likely to have asthenospermia. Asians (OR 0.73; 95% CI 0.57-0.94) and Indo-Canadians (OR 0.58; 95% CI 0.35-0.99) were less likely to have teratozospermia. No differences were seen for vitality. No differences were seen for FSH levels, however, Asians (p<0.01) and Indo-Canadians (p<0.01) were more likely to have lower testosterone. CONCLUSIONS:Our study illustrates that variations in semen analyses and hormones exist in men with infertility. This may provide insight into the workup and management for infertile men from different ethnicities.

OBJECTIVES:Metformin has been associated with improved survival outcomes in various malignancies. However, studies in kidney cancer are conflicting. We performed a systematic review and meta-analysis to evaluate the association between metformin and kidney cancer survival. MATERIALS AND METHODS:We searched Medline and EMBASE databases from inception to June 2017 to identify studies evaluating the association between metformin use and kidney cancer survival outcomes. We evaluated risk of bias with the Newcastle-Ottawa scale. We pooled hazard ratios (HRs) for recurrence-free, progression-free, cancer-specific, and overall survival using random effects models, and explored heterogeneity with metaregression. We evaluated publication bias through Begg's and Egger's tests, and the trim and fill procedure. RESULTS:We identified 9 studies meeting inclusion criteria, collectively involving 7426 patients. Five studies were at low risk of bias. The direction of association for metformin use was toward benefit for recurrence-free survival (HR, 0.99; 95% confidence interval [CI], 0.36-2.74), progression-free survival (pooled HR, 0.84; 95% CI, 0.66-1.07), cancer-specific (pooled HR, 0.72; 95% CI, 0.48-1.09), and overall survival (pooled HR, 0.73; 95% CI, 0.50-1.09), though none reached statistical significance. Metaregression found no study-level characteristic to be associated with the effect size, and there was no strong evidence of publication bias for any outcome. CONCLUSIONS:There is no evidence of a statistically significant association between metformin use and any survival outcome in kidney cancer. We discuss the potential for bias in chemoprevention studies and provide recommendations to reduce bias in future studies evaluating metformin in kidney cancer.

INTRODUCTION:Diabetes has been associated with worse survival outcomes in various malignancies; however, there are conflicting data in kidney cancer. Determining whether diabetes is associated with survival in kidney cancer may help guide treatment in a comorbid patient population. METHODS:We used the Canadian Kidney Cancer information system database to identify patients undergoing partial or radical nephrectomy between 1989 and 2017 for localized renal cell carcinoma at 16 institutions across Canada. We derived inverse probability of treatment weights (IPTW) from a propensity score model based on various clinical, surgical, and pathological characteristics. We used Cox proportional hazard models to evaluate the association between diabetes and cancer-specific and overall survival, in the sample weighted by the IPTW. RESULTS:4828 patients met inclusion criteria, of whom 948 (19.6%) were diabetic. Median follow-up in those without death was 26.6 months (interquartile range 9.7-53.8). Among the entire cohort, 901 deaths were from any cause, and 299 deaths from kidney cancer. Before propensity score methods, diabetics were older, more likely to have comorbidities and clear cell histopathology. After propensity score adjustment, all characteristics were balanced between groups (standardized difference <0.10). IPTW-adjusted Cox proportional hazard models demonstrated no significant association between diabetes and cancer-specific (hazard ratio 1.13, 95% confidence interval 0.78-1.62), or overall survival (hazard ratio 1.14, 95% confidence interval 0.94-1.38). CONCLUSIONS:Our multi-centre study found that diabetes and nondiabetics have similar survival following nephrectomy for kidney cancer.

PURPOSE:Active surveillance (AS) for testicular nonseminomatous germ cell tumors (NSGCT) is widely used. Although there is no consensus for optimal treatment at relapse on surveillance, globally patients typically receive chemotherapy. We describe treatment of relapses in our non-risk-adapted NSGCT AS cohort and highlight selective use of primary retroperitoneal lymph node dissection (RPLND). METHODS:From December 1980 to December 2015, 580 patients with clinical stage I NSGCT were treated with AS, and 162 subsequently relapsed. First-line treatment was based on relapse site and extent. Logistic regression was used to explore factors associated with need for multimodal therapy on AS relapse. RESULTS:= .008) in patients undergoing RPLND. When RPLND was performed with normal markers, 82% required no further treatment. Second relapse occurred in 30 of 162 patients (18.5%). With median follow-up of 7.6 years, there were five deaths (3.1% of AS relapses, but 0.8% of whole AS cohort) from NSGCT or treatment complications. CONCLUSION:The retroperitoneum is the most common site of relapse in clinical stage I NSGCT on AS. Most are cured by single-modality treatment. RPLND should be considered for relapsed patients, especially those with disease limited to the retroperitoneum and normal markers, as an option to avoid chemotherapy.

Several studies demonstrate that use of commonly prescribed medications is associated with improved survival in various malignancies. Methods of classifying medication use in many of these studies, however, do not account for intermittent or cumulative use. Moreover, there are limited data in kidney cancer. Therefore, we performed a population-based cohort study utilizing healthcare databases in Ontario, Canada. We identified patients aged ≥65 with an incident diagnosis of kidney cancer between 1997 and 2013 and examined use of nine putative anti-neoplastic medications using prescription claims. Cox proportional hazard models evaluated the association of medication exposure on cancer-specific and overall survival. We conducted three separate analyses: the effect of cumulative duration of exposure to the study medications on outcomes, the effect of current exposure (in a binary nature) and the effect of exposure at diagnosis. During the 16-year study period, we studied 9,124 patients. Increasing cumulative use of angiotensin-converting enzyme inhibitors, non-steroidal anti-inflammatory drugs (NSAIDs) and selective serotonin reuptake inhibitors were associated with markedly improved cancer-specific survival; increasing use of NSAIDs was associated with markedly improved overall survival. These results were generally discordant with analyses evaluating the effect of current use and exposure at diagnosis. In conclusion, pharmacoepidemiology studies may be sensitive to the method of analysis; cumulative use analyses may be the most robust as it accounts for intermittent use and supports a dose-outcome relationship. Prospective studies are needed to confirm whether patients diagnosed with kidney cancer should be started on an angiotensin-converting enzyme inhibitor, NSAID or selective serotonin reuptake inhibitor to improve survival.

INTRODUCTION/BACKGROUND:Non-muscle-invasive bladder cancer (NMIBC) accounts for 75-85% of all urothelial bladder cancers (UBC). Many UBC patients are also afflicted by diabetes mellitus (DM). It has been postulated that several oral hypoglycemic agents could impact disease-specific survival (DSS), but the data are sparse among NMIBC patients. Our primary objective was to evaluate the impact of metformin on DSS and overall survival (OS) in NMIBC patients. METHODS:This is a retrospective, population-based study that used linked administrative databases to identify diabetic patients ≥66 years who were subsequently diagnosed with NMIBC in Ontario between 1992 and 2012. Cumulative use of metformin and other hypoglycemic agent were calculated before and after NMIBC diagnosis. DSS and OS were estimated using multivariable competing risk and Cox proportional hazards models, respectively. RESULTS:A total of 1742 subjects were included in the study. After a median followup of 5.2 years, 1122 (64%) had died, including 247 (15%) deaths as a result of UBC. On multivariable analysis, cumulative duration of metformin use after NMIBC diagnosis did not appear to impact DSS (hazard ratio [HR] 1.1; 95% confidence interval [CI] 0.92-1.2), whereas glyburide use appeared to have a detrimental effect (HR 1.17; 95% CI 1.02-1.3). None of the other hypoglycemic agents had an impact on OS. CONCLUSIONS:In this large, population-based study, we have provided further evidence that metformin use does not significantly impact DSS among diabetic patients diagnosed with NMIBC. However, our findings demonstrate that glyburide use inversely affects DSS. The detrimental effect of glyburide on DSS will require further validation.