Role of pelvic lymph node dissection in lymph node-negative patients with invasive bladder cancer.

OBJECTIVES The role of pelvic lymphadenectomy in patients with lymph node-negative bladder cancer at radical cystectomy (RC) has not yet been examined in detail. We retrospectively reviewed patients who underwent RC with pelvic lymphadenectomy for bladder cancer from January 1987 to March 2008. METHODS We identified consecutive data on 169 patients who underwent RC for bladder cancer. The mean follow-up was 64 months (range: 1-253 months). Node-positive status (pN(+)) was seen in 16 patients and 91 were diagnosed as node-negative (pN(-)). The lymph node status of the remaining 62 patients was unclear (pN(x)). We analysed the association between lymph node status and cancer-specific survival (CSS), and examined the role of the number of retrieved lymph nodes, particularly in pN(-). RESULTS The median number of retrieved nodes was 12.9 and 10.2 for stage pN(+) and stage pN(-), respectively. In 91 patients with pN(-), multivariate analysis revealed that pathological T3-4 (P = 0.0276) and less than nine retrieved lymph nodes (P = 0.0108) were independent risk factors for CSS. In a subgroup of 83 patients with pT3-4, Kaplan-Meier curves showed that the 5-year CSS rate in pN(-) patients with less than nine retrieved lymph nodes was 38.8%, which was extremely similar to the 40.8% in pN(+) and 45.1% in pN(x). CONCLUSIONS Our results demonstrate that at least nine lymph nodes should be removed to improve the survival of pN(-) patients at RC and lymphadenectomy, and would provide information not only on prognosis but also on the therapeutic impact on pT3-4 invasive bladder cancer.