PARTIAL NEPHRECTOMY AND RADICAL NEPHRECTOMY OFFER SIMILAR CANCER OUTCOMES IN RENAL CORTICAL TUMORS 4 cm OR LARGER ROBERT E. MITCHELL, SCOTT M. GILBERT, ALANA M. MURPHY, CARL A. OLSSON, MITCHELL C. BENSON, AND JAMES M. MCKIERNAN ABSTRACT Objectives. To determine whether the type of surgery (partial nephrectomy [PN] versus radical nephrec- tomy [RN]) has any effect on cancer outcome for renal cortical tumors 4 cm or larger. PN outcomes for large renal cortical tumors have been shown to be worse than outcomes for smaller tumors, but the upper limit of tumor diameter amenable to PN remains controversial. Methods. We identified 33 patients from the Columbia University Comprehensive Urologic Oncology Database who underwent PN between 1988 and 2004 for renal cortical tumors 4 cm or larger. Each was matched with 2 patients undergoing RN on the basis of the tumor diameter. A survival analysis was conducted using the Kaplan-Meier method, and any differences between the two groups were compared using the log-rank test. The Cox regression model was used to determine which variables affected survival. Results. The estimated 5-year recurrence-free survival rate was 93.5% for the PN group and 83.3% for the RN group (P = 0.471). The estimated 5-year disease-specific survival rate was 96.2% for the PN group and 97.8% for the RN group (P = 0.893). Only tumor diameter had an impact on recurrence-free survival in the univariate (P = 0.005) and multivariate (P = 0.008) Cox regression models. Surgical technique had no impact on disease recurrence. Conclusions. The results of our study have shown that cancer outcomes after PN do not differ from outcomes after RN for tumors of 4 cm or greater in diameter. The upper limit of 4 cm appears to have been determined arbitrarily. It is no longer advisable to restrict PN to patients with tumors smaller than 4 cm in diameter. UROLOGY 67: 260–264, 2006. © 2006 Elsevier Inc. T he role of surgery in the therapy of renal cortical tumors (RCTs) is firmly established, but experi- ence and technology have shown in the past decade that partial nephrectomy (PN) can be as effective in cancer control as radical nephrectomy (RN). This nephron-sparing approach to RCTs was initially ex- plored in patients with contraindications to RN but is now widely performed electively. 1 Nevertheless, the appropriate upper limit of tumor size that is amena- ble to PN remains controversial. The outcomes after PN for tumors less than 4 cm in diameter have been shown to be equivalent to those of RN. 2,3 The out- comes after PN for RCTs 4 cm or larger are unequiv- ocally worse, and this observation has, in part, led to the substratification of the Stage T1 classification into T1a and T1b. 4 However, the outcomes after RN for RCTs 4 cm or greater are also worse than the out- comes after RN for smaller tumors. The 4-cm cutoff has been contested by several investigators whose data have indicated that larger tumors may be equally amenable to PN. 5,6 In the current study, the efficacy of PN was analyzed by case-matching with RN “con- trols.” By matching according to size and other dis- ease parameters, we sought to determine whether type of surgery (RN versus PN) has any effect on cancer outcome for tumors 4 cm or greater. MATERIAL AND METHODS The Columbia University Comprehensive Urologic Oncol- ogy Database (approved by Columbia’s institutional review board) was reviewed, and 830 patients were identified who had undergone renal surgery for presumed RCTs from 1988 to From the Department of Urology, Columbia University College of Physicians and Surgeons, New York, New York Reprint requests: James M. McKiernan, M.D., Department of Urology, Columbia University School of Medicine, 161 Fort Washington Avenue, 11th Floor, New York, NY 10032. E-mail: jmm23@columbia.edu Submitted: June 21, 2005, accepted (with revisions): August 25, 2005 ADULT UROLOGY © 2006 ELSEVIER INC. 0090-4295/06/$32.00 260 ALL RIGHTS RESERVED doi:10.1016/j.urology.2005.08.057