AUA 2020: Long Term Oncologic Outcomes of Surgically Treated Renal Oncocytoma

(UroToday.com) Increasing utilization of cross-sectional imaging in primary care and emergency departments had led to an increase in the incidental diagnosis of renal masses. While the majority of these are renal cell carcinoma, a number of other entities are on the differential diagnosis including renal oncocytomas. Long-term outcomes of patients who undergo surgery for renal oncocytomas are sparse and, for the most part, non-contemporaneous. In a podium presentation at the American Urologic Association Virtual Annual Meeting, Dr. Matvey Tsivian and colleagues presented results of a single center study of patients surgically treated for renal oncocytoma at the Mayo Clinic.



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.

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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).

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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
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