Impact of Renal Lesion Size on Perioperative and Pathologic Outcomes in Patients Undergoing Laparoscopic Partial Nephrectomy

Background and Purpose: The size of renal lesions managed with laparoscopic partial nephrectomy (LPN) has been increasing, especially as surgical volume and experience matures. The objective of this study was to assess the perioperative and pathologic outcomes of LPN when stratifying for size of renal lesion. Patients and Methods: A retrospective review of LPN performed at the University of Chicago by a single surgeon (ALS) between October 2002 to July 2007 was performed. Patients (153) were then stratified into three groups according to radiographic diameter of the lesion: <= 2 cm (group A), 2 to 4 cm (group B), and >= 4 cm (group C). Perioperative, operative, and pathologic data were compared using analysis of variance and Pearson test. Moreover, serum creatinine and creatinine clearance (Cockcroft-Gault) were assessed postoperatively. Results: With regard to operative parameters, operative time was significantly longer in renal lesions >2 cm (P = 0.0012), and the need for collecting system repair was also more prevalent as lesion size increased (P < 0.0001). Warm ischemia time was longest with lesions 2 to 4 cm (35.3 min) compared with masses <= 2 cm (27.2 min; P < 0.001) or >= 4 cm (30.3 min; P = 0.028). All other variables were similar among the three groups, including the rates of positive surgical margins, complications, estimated blood loss, conversion, and transfusion. Comparison of pathologic data suggests smaller lesions are more likely to be of lower grade compared with larger lesions. Postoperative renal function did not differ among the groups with a mean follow-up of 19.9 months. Conclusions: Although LPN for renal masses 2 to 4 cm necessitated longer warm ischemia, short- term postoperative renal function was not affected by lesion size. Differences in warm ischemia time cannot be attributed solely to lesion size but are likely influenced by a combination of tumor size, location, and depth. LPN can be performed safely in selected patients with larger renal lesions.