Simple Enucleation is Equivalent to Traditional Partial Nephrectomy for Renal Cell Carcinoma: Results of a Nonrandomized, Retrospective, Comparative Study

Purpose: The excision of the renal tumor with a substantial margin of healthy parenchyma is considered the gold standard technique for partial nephrectomy. However, simple enucleation showed excellent results in some retrospective series. We compared the oncologic outcomes after standard partial nephrectomy and simple enucleation. Materials and Methods: We retrospectively analyzed 982 patients who underwent standard partial nephrectomy and 537 who had simple enucleation for localized renal cell carcinoma at 16 academic centers between 1997 and 2007. Local recurrence, cancer specific survival and progression-free survival were the main outcomes of this study. The Kaplan-Meier method was used to calculate survival functions and differences were assessed with the log rank statistic. Univariable and multivariable Cox regression models addressed progression-free survival and cancer specific survival. Results: Median followup of the patients undergoing traditional partial nephrectomy and simple enucleation was 51 +/- 37.8 and 54.4 +/- 36 months, respectively (p = 0.08). The 5 and 10-year progression-free survival estimates were 88.9 and 82% after standard partial nephrectomy, and 91.4% and 90.8% after simple enucleation (p = 0.09). The 5 and 10-year cancer specific survival estimates were 93.9% and 91.6% after standard partial nephrectomy, and 94.3% and 93.2% after simple enucleation (p = 0.94). On multivariable analysis the adopted nephron sparing surgery technique was not an independent predictor of progression-free survival (HR 0.8, p = 0.55) and cancer specific survival (HR 0.7, p = 0.53) when adjusted for the effect of the other covariates. Conclusions: To our knowledge this is the first multicenter, comparative study showing oncologic equivalence of standard partial nephrectomy and simple enucleation.