Clinical Risk Factors Associated With Small Renal Mass Malignant Histology in a Multi-Ethnic Population Undergoing Partial Nephrectomy

Introduction: Small renal masses (SRMs) are often incidentally diagnosed, and a large proportion are malignant. However, there is a paucity of data describing predictors of malignancy in minority patients with SRMs. Thus, our goal was to examine clinical risk factors associated with SRM malignant histology in patients undergoing partial nephrectomy (PN) a diverse, urban academic center. Materials and Methods: Patients with a SRM undergoing PN at a single institution between 2010 to 2018 were reviewed. Demographic, clinical, and imaging characteristics were compared to pathology results. Logistic regression was used to examine associations between demographic/clinical variables for malignant and high-grade histology. Results: In total, 331 patients who underwent PN for SRM were included. Of those, 264 (79.8%) had malignant histology while 67 (20.2%) had benign histology. The proportions of men and of current smokers were significantly higher among patients with malignant histology. In multivariate models, non-Hispanic Black (NHB) patients had increased odds of having malignant histology (OR 2.46, 95% CI: 1.01-5.99, P =.048) and current smokers (OR = 4.02; 95% CI 1.14-14.18, P =.031). Hispanic patients had a 3-fold increased risk of high-grade RCC (OR 3.06, 95% CI: 1.19-7.87, P = 0.02) compared to Non-Hispanic White patients. Conclusion: In our population, male sex, smoking, and NHB race/ethnicity was associated with an increased risk of malignancy in patients undergoing partial nephrectomy for SRM. Older age and Hispanic race/ethnicity were associated with high grade RCC. Our results suggest that urologists should exercise a higher level of vigilance in managing and treating SRM among NHB and Hispanic patients.