Functional analysis of elective nephron-sparing surgery vs radical nephrectomy for renal tumors larger than 4 cm.

Objective: To preserve renal function, nephron sparing surgery (NSS) for renal tumors should be performed. Little is known about perioperative morbidity and long-term functional outcome of patients after elective NSS compared with radical nephrectomy (RN) in renal tumors >4 cm.

Methods: Eight-hundred twenty-nine patients were treated with either RN (n = 641) or NSS (n = 188) for renal tumors >4 cm. After pairing the cohort for age, grading, TNM, size, gender, and preoperative renal function and excluding patients with imperative indication and metastases, 247 patients remained for functional analysis. Serum creatinine (SCr) values were used to estimate glomerular filtration rate (eGFR) via Modification of Diet in Renal Disease. Chronic kidney disease (CKD) was defined as eGFR <60 mL/min/1.73 m(2) and regression analyses were used to identify clinical risk factors for CKD and perioperative complications stratified by the Clavien-Dindo score.

Results: The Charlson comorbidity index was similar between patients undergoing NSS (n = 101) and RN (n = 146) (P = .583). The complication rates did not differ significantly between both groups (P = .091). Age (OR 0.94, P = .009), ASA score 3+4 (OR 3.55, P = .004), RN (OR 10.75, P < .001), and preoperative eGFR (OR 1.06, P < .001) were independent risk factors for developing CKD postoperatively, whereas tumor size had no impact (OR 1.01, P = .245). Overall survival was comparable between the groups (P = .896).

Conclusions: Although overall survival was similar, patients undergoing RN for renal tumors >4 cm had a significantly higher risk of developing CKD than patients treated with NSS. Complication rate did not differ significantly between both groups, even for tumors >7 cm. Our findings support elective NSS for tumors >4 cm, whenever NSS is technically feasible for maintaining renal function.