Natural History of Renal Cortical Neoplasms During Active Surveillance With Follow-up Longer Than 5 Years

ObjectivesTo present our experience with patients who elected active surveillance for renal cortical neoplasms (RCNs) with ≥5 years of follow-up. Few data are available regarding the long-term natural history of RCNs during surveillance.MethodsWe retrospectively reviewed our urologic oncology database and identified 44 patients with 51 RCNs who had received active surveillance for >5 years of follow-up. The patient and tumor characteristics and tumor growth rate and overall survival data were evaluated.ResultsThe median patient age was 71.7 years (range 55-92), with 32 patients (72.7%) having a Charlson comorbidity index of ≥2. The median tumor size was 2.67 cm (range 0.9-8.6) at diagnosis. Biopsy was performed in 17 patients (38.6%). Of these 17 patients, clear cell renal cell carcinoma was diagnosed in 15 and papillary renal cell carcinoma in 2 patients. The median follow-up was 77.1 months (range 60-137), and the median growth rate was 0.15 cm/y. Of these patients, 2 (4.5%) required delayed intervention. One underwent laparoscopic radical nephrectomy because of a high tumor growth rate, and one elected to withdraw from active surveillance because of personal anxiety, despite having a stable tumor size for 72 months. The latter patient underwent laparoscopic renal cryoablation. Histopathologic examination revealed clear cell renal cell carcinoma in both cases. No metastases or cancer-related deaths occurred in our cohort; 1 patient died of cardiovascular disease.ConclusionsMost RCNs undergoing surveillance for >5 years grew slowly. The metastatic potential appeared minimal in patients who demonstrated low or absent tumor growth for a long period.