Is Routine Renal Tumor Biopsy Associated with Lower Rates of Benign Histology following Nephrectomy for Small Renal Masses?

Abstract

Renal tumor biopsies have been proposed as a management alternative to avoid treatment of benign or low risk small renal masses. However, many urologists are reluctant to recommend renal tumor biopsy because they feel its result frequently will not impact management. Our primary objective was to evaluate if centers that routinely favor renal tumor biopsy have lower rates of benign histology after surgery than centers where a selective renal tumor biopsy approach is used. This was a retrospective multicenter study of patients who underwent partial or radical nephrectomy for a lesion suspicious for localized renal cell carcinoma which measured 4 cm or less (cT1a and pT1a or pT3a) between 2013 and 2015. A logistic regression model was used to examine whether the odds of obtaining a benign tumor following surgery differed between centers that routinely favor renal tumor biopsy and centers where a selective renal tumor biopsy approach is used. A total of 542 small renal masses in 516 patients were included in study. The rate of histologically benign tumors after surgery was 11%. This rate was significantly lower at centers that routinely favor renal tumor biopsy than at centers where a selective renal tumor biopsy approach is used (5% vs 16%, p<0.001). On multivariable analysis older age, smaller tumors and centers where a selective renal tumor biopsy approach is used were significantly associated with greater odds of finding a histologically benign tumor postoperatively. Compared to centers that routinely favor renal tumor biopsy the odds of finding a benign tumor at surgery was 4 times more likely at centers where a selective renal tumor biopsy approach is used (OR 4.1, 95% CI 1.9-8.3). Routine renal tumor biopsy reduces surgery for benign tumors and the potential for short-term and long-term morbidity associated with these procedures. This study suggests that routine renal tumor biopsy may be a valuable tool to decrease overtreatment of small renal masses.