Time-dependent change in relapse sites of renal cell carcinoma after curative surgery

We investigated time-dependent changes in the relapse features of renal cell carcinoma (RCC) after curative surgery. Between 1985 and 2015, 1398 patients with RCC (1226 clear cell RCC, 89 papillary RCC, and 53 chromophobe RCC) underwent curative surgery at Yokohama City University Hospital and its affiliated hospitals. We retrospectively reviewed the clinicopathologic factors of patients with relapse after surgery. Median follow-up was 56.3 months. Recurrence occurred in 245 patients (217 clear cell RCC, 12 papillary RCC, and 3 chromophobe RCC). Papillary RCC and chromophobe RCC had no recurrence beyond 5 years after surgery, but 20 cases of clear cell carcinoma had recurrence beyond 10 years after surgery. The typical recurrence sites of clear cell RCC were lung (46.6%), bone (17.9%), liver (7.6%), and lymph nodes (6.5%). The proportion of recurrences at these typical sites was 83.9% for recurrences within 5 years, 76.3% between 5 and 10 years, and 40.0% beyond 10 years. In contrast, the proportion of retroperitoneal organ recurrence, including contralateral kidney, pancreas, and adrenal glands, increased with increasing time after surgery. Interestingly, the hazard ratio of typical site relapse decreased whereas that of retroperitoneal organ relapse increased in a time-dependent manner. In summary, clear cell RCC showed potential to relapse beyond 10 years after surgery. Recurrence at typical sites decreased whereas retroperitoneal organ recurrence increased in a time-dependent manner. Clinicians should check for recurrence at various sites beyond 10 years, especially in clear cell RCC.