Presentation Authors: Aeen Asghar*, Andrew McIntosh, Philadelphia, PA, Zachary Smith, Chicago, IL, Neil Kocher, Hershey, PA, Ziho Lee, Philadelphia, PA, Nimrod Barashi, Chicago, IL, Jay Raman, Hershey, PA, Scott Eggener, Chicago, IL, Robert Uzzo, Alexander Kutikov, Philadelphia, PA
Introduction: The decision to perform partial nephrectomy (PN) for an organ-confined >4 cm renal mass is often complex. Albeit often feasible, oncologic safety of PN in this cohort is debated. Yet, a significant portion of large renal masses that undergo radical nephrectomy (RN) prove benign or indolent. Since renal mass biopsy (RMB) is highly accurate in diagnosing oncocytic neoplasms, we assessed whether patients with a large renal mass treated by RN could have benefited from pre-operative RMB.
Methods: We queried prospectively maintained kidney cancer databases from three institutions to identify patients who underwent RN for localized renal mass >4 cm. We excluded patients with nodal or distant metastases. Clinicopathologic variables, mass anatomic complexity and patient co-morbidities were indexed. Wilcoxon-Mann-Whitney test was used to compare patients with oncocytic neoplasms to the remainder of the cohort.
Results: A total of 722 patients (median age 62 years, 64% male, 83% Caucasian, median serum creatinine [SCr] 0.97 ng/dL, median Charlson comorbidity index [CCI] 1) underwent RN for localized >4 cm renal mass (median tumor size 7 cm [IQR 4-9.1 cm]). Final pathology revealed that 12.5% (n=91) of patients harbored oncocytic neoplasm (n=28, 3.8%) or chromophobe RCC (n=63, 8.7%). When stratified by tumor size, oncocytic tumors comprised 9.3% of 4-7 cm masses, 16.0% of â‰¥7-10 cm masses, and 17.6% of â‰¥10 cm tumors. Median RENAL Nephrometry Score was 9 (IQR 4-10). Oncocytic tumors were more common in younger patients (56.5 vs. 62.5 years, p < 0.01), larger tumors (7.6 vs 6.8 cm, p=0.02), those with lower CCI (0 vs. 2, p=0.01) and lower pre-operative SCr (0.9 vs. 1.0 mg/dL, p=0.02).
Conclusions: Approximately 1 in 8 patients with renal mass >4 cm harbored benign or low-risk oncocytic lesions. Although these patients had larger tumors, they were younger and less co-morbid than patients with oncologically higher risk lesions. As such, RMB may help calibrate the complex choice of PN vs. RN in patients with large renal mass.