ABSTRACT
PURPOSE: To determine the malignant potential in clinically localised small renal cell carcinoma (RCC) (≤4cm) in patients using postoperative pathologic outcomes. MATERIALS AND METHODS: We performed a retrospective analysis of 2,085 patients in 7 urology centres with clinical T1a RCC who underwent nephrectomy. The pathologic upstaging group (PUG) was defined by pathologic T3a after the operation. Multivariate analyses were used to examine predicting factors for the risk of PUG. Next, Kaplan-Meier analysis was used to examine the PUG for worse recurrence-free survival during the follow-up period. RESULTS: The PUG had 73 patients (3.5%); they were older and had a larger tumour size than the other patients (all p<0.001). After adjusting for clinical characteristics, age (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.02–1.06) and tumour size greater than 3 cm (OR, 1.94; 95% CI, 1.21–3.11) were found to be independent predictors for the PUG after nephrectomy. Furthermore, the PUG had worse recurrence-free survival during the follow-up period. CONCLUSIONS: In this multi-institution analysis, RCC 3 cm or greater in older patients had a high malignant potential compared to relatively small tumours in younger patients. These results may be helpful for stratifying patients to manage small renal masses.