Cytoreductive nephron-sparing surgery does not appear to undermine disease-specific survival in patients with metastatic renal cell carcinoma

BACKGROUND. The role of nephron-sparing surgery (NSS) showed promise in patients with metastatic renal cell carcinoma (MRCC). The disease-specifrc survival of patients with MRCC was compared according to the type of surgery, NSS (N = 45) versus radical nephrectomy (RN) (N = 732), in unmatched and matched analyses. METHODS. Kaplan-Meier, life tables, log-rank test, and univariate as well as multivariate Cox regression analyses addressed disease-specific survival of NSS versus RN patients. Subsequently, up to 4 RN cases were matched with each NSS case for TNM stage, Fuhrman grade, and histology. Then, disease-specific survival differences were tested with the log-rank statistic. Finally, the sample size necessary to achieve 80% power in survival analyses between the 2 groups (NSS vs RN) was calculated. RESULTS. Of 45 NSS cases, 38 were matched with 99 of 732 RN cases. First, in multivariate unmatched analyses RN predisposes to 1.7-fold higher RCC-specific mortality rate; second, in matched analyses RN predisposes to 1.5-fold higher RCC-specific mortality rate; and third, both analyses failed to demonstrate statistically significant differences. Based on these findings it could be postulated that until further data become available, NSS does not appear to undermine RCC-specific survival in carefully selected patients with MRCC. The power analyses demonstrated that at least 146, 48, and 76 observations per arm are necessary at 1, 2, and 3 years, respectively, to confirm survival equivalence. CONCLUSIONS. Although the data were limited in size and completeness, they may indicate that RCC-specific survival may not be undermined if NSS is performed in properly selected cases.