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BACKGROUND:
Intraoperative frozen section sampling of the parenchymal margin during robot-assisted laparoscopic partial nephrectomy (RALPN) is often performed. The sampling may increase warm ischemia time during an on-clamp RALPN. The objective of the study is to determine whether frozen section adds useful information that can change intraoperative management.
METHODS:
A prospectively-maintained RALPN database was reviewed. The database included all patients undergoing surgery by two surgeons between 2008 and 2013. The frozen section of the deep tumor margin (FS-DTM), final deep tumor margin (DTM) status, and tumor pathology were reviewed.
RESULTS
A total of 115 patients who underwent RALPN were included in the study. Mean tumor size was 3 cm, and mean R.E.N.A.L. score was 8 (range 4 to 11). Four patients were found to have focal positive surgical margins on final tumor pathology. Three of the four positive margins were in renal cell carcinoma, while the fourth was an oncocytoma. The frozen section deep tumor margin (FS-DTM) and final deep tumor margin (DTM) wre negative in all four patients.
Three patients had positive FS-DTM. Re-resection was performed in all three patients with negative repeat FS-DTM.
One patient demonstrated positive FS-DTM of a deep, complex renal mass. The mass extended into the renal sinus and addition resection could not be performed; the kidney was removed with residual tumor noted on final pathology.
No patients demonstrated local radiographic or clinical recurrence with a mean of 17 months follow-up.
CONCLUSIONS
Frozen section of the deep tumor margin can add useful information to intraoperative management during RALPN. Patients found to have a PSM on FS-DTM can undergo re-resection of additional tissue. FS-DTM can be negative even in the presence of a focally positive surgical margin, and thus caution should be used in interpreting the results. Collaboration with the Pathology department regarding interpretation of margin status is important.