Comparative Analysis of Surgery, Thermal Ablation, and Active Surveillance for Renal Oncocytic Neoplasms.

OBJECTIVE: To compare oncological and procedural outcomes for renal oncocytic tumors treated with surgery, thermal ablation, or active surveillance.

METHODS: Clinical and pathologic data were collected for consecutive patients with a histologic diagnosis of oncocytoma, oncocytic neoplasm, or chromophobe renal cell cancer (chRCC) from 2003 to 2016. Independent pathology and radiology reviews were performed for this study.

RESULTS: Of 171 patients, tumor histology included oncocytoma (n = 122), chRCC (n = 47), and oncocytic neoplasm not otherwise specified (n = 2). At the initial diagnosis, 67, 14, and 90 patients were treated with surgery, thermal ablation, and active surveillance. In 3 of 19 patients (16%) who had biopsy and subsequent surgery, diagnosis changed from oncocytoma to chRCC. The median follow-up was 39.9 months with no difference among choices of treatment modalities (P = .33). Of 90 patients who began active surveillance, 32 (36%) switched to active treatments (19 underwent thermal ablation and 13 underwent surgery). The median linear growth rate for patients on active surveillance was 1.2 mm/y. No patients who were managed with active surveillance developed metastatic renal cell cancer (mRCC). mRCC was identified in 3 patients and was the cause of death in 2 patients. Patients who developed metastatic disease presented with symptomatic tumors of >4 cm and were treated with immediate surgery. For oncocytic masses of ≤4 cm (n = 126), the 5-year cancer-specific survival was 100%.

CONCLUSION: Renal oncocytic neoplasms have favorable oncological outcomes. Active surveillance is safe and is the preferred management for small (≤4 cm) oncocytic renal tumors in selected patients.