Utility of intraoperative frozen section during robot-assisted partial nephrectomy: a single institution experience

Intraoperative frozen section (FS) analysis has been regarded as a paramount tool for immediate evaluation of tumor margin status during partial nephrectomy procedures. The aim of this study was to assess the utility of FS during robot-assisted partial nephrectomy (RAPN).

A retrospective review of our Institutional Review Board-approved prospectively maintained minimally invasive partial nephrectomy database yielded 342 consecutive RAPN procedures from June 2007 to September 2011. Of these, the initial 128 cases underwent FS evaluation, whereas the following 214 cases did not. Patient demographics, perioperative outcomes, and final pathology results were analyzed and compared between the two groups.

Body mass index, Charleson Comorbidity Index, tumor size, renal score, preoperative creatinine level, and estimated glomerular filtration rate (eGFR) were similar between both groups. Operative time was significantly longer in the no-FS group (193 vs 180 min; P=0.04). Warm ischemia time (median 19 vs 19 min), estimated blood loss (150 vs 200 mL), postoperative creatinine level (1.0 vs 1.1 mg/dL), and postoperative eGFR (75.6 vs 75.9) were similar between the no-FS group and FS group, respectively. Complications occurred in 32 (15.0%) and 31 (24.2%) cases in no-FS and FS, respectively (P=0.06). Final pathology results demonstrated seven cases of positive margins, 1 (1%), in the FS group and 6 (3%) in the no-FS group (P=0.19). Of the cases with positive margins at final pathology analysis, a R.E.N.A.L. score of 3/3 was found on closeness to renal sinus. Overall, three intraoperative positive margins were noted in the FS group (2.3%): One patient underwent radical nephrectomy and one reresection; one case was managed with observation only.

Routine application of FS analysis during RAPN seems to provide a limited benefit. FS might be advisable for tumors with sinus invasion because they seem to carry a higher likelihood of positive surgical margin at final pathology determination.