The authors identified patients who underwent surgical resection of a renal mass with a final pathologic diagnosis of renal oncocytoma. Each case was reviewed by a genitourinary pathologist to confirm the diagnosis. Patients were then followed to identify disease recurrence on the basis of new radiographic evidence of a concerning renal mass warranting surveillance or intervention. Pathology from recurring disease was analyzed when available. Patient characteristics were descriptively summarized and oncologic outcomes were described using the Kaplan-Meier method.
Between 1970 and 2012, the authors identified a total of 561 patients who underwent resection of renal oncocytoma. Median tumor size was 3.5cm and clinical stage was T1 in 87% of patients. With respect to initial resection approach, 47% underwent open partial nephrectomy and 28% underwent open radical nephrectomy while the remainder underwent minimally invasive surgery. 102 patients (18%) had multifocal disease including 52 bilateral tumors at diagnosis.
Over a median follow up of 10.6 years, 24 patients experienced tumor recurrence at a median of 6 years. Histology of these recurrent tumors demonstrated oncocytomas in 12, renal cell carcinoma in 2, and unknown histology in 10.
Overall, estimated recurrence-free survival was 98, 96, and 94% at 5, 10 and 20 years, respectively.
For those with multifocal disease, recurrence-free survival was somewhat lower at 95, 87, and 87% at 5, 10, and 20 years, respectively, corresponding to a significantly increased risk of recurrence on univariate analysis (HR=3.92, 95% CI 1.75-8.75, p<0.001).
In summary, for patients with renal oncocytoma who undergo surgical resection, recurrence rates are low though initial multifocality is a risk factor for increased risk of recurrence.
Presented by: Matvey Tsivian, MD, Mayo Clinic, Rochester, MN
Written by: Christopher J.D. Wallis, Urologic Oncology Fellow, Vanderbilt University Medical Center Contact: @WallisCJD on Twitter at the 2020 American Urological Association (AUA) Annual Meeting, Virtual Experience #AUA20, June 27- 28, 2020