Effect of a minimum lymph node policy in radical cystectomy and pelvic lymphadenectomy on lymph node yields, lymph node positivity rates, lymph node density, and survivorship in patients with bladder cancer.

摘要

BACKGROUND: Extended pelvic lymphadenectomy (PLND) during radical cystectomy (RC) reportedly improves bladder cancer-specific survival. Lymph node counts are often a proxy for the extensiveness of a dissection. In the current study, the impact of an institutional policy requiring a minimum number of lymph nodes was assessed. METHODS: Patients undergoing RC and PLND for invasive bladder cancer between March 2000 and February 2008 were retrospectively reviewed at the study institution. Beginning March 1, 2004, a policy was established that at least 16 lymph nodes had to be examined. Specimens with <16 lymph nodes were resubmitted (including any fat) to detect additional lymph nodes. Lymph node yields, lymph node positivity, lymph node density (LND), and survivorship before and after policy implementation were compared. RESULTS: A total of 147 patients underwent surgery 4 years before policy implementation and 202 underwent surgery 4 years after. The median number of lymph nodes increased from 15 to 20. Percentage of cases with >or=16 lymph nodes increased from 42.9% to 69.3% (P <.01). The lymph node positivity rates did not change significantly, but the proportion of patients with LND <20% increased from 43.9% to 65.5% (P = .04). Overall survival increased from 41.5% to 72.3% (P <.01). Univariate and multivariate regression demonstrated that policy implementation, and subsequent increase in median lymph node yield, decreased mortality risk by 30% (hazards ratio [HR], 0.70; P = .04) and 48% (HR, 0.52; P = .01), respectively. CONCLUSIONS: Thorough evaluation of PLND specimens obtained at RC can be influenced by an institutional policy mandating a minimum number of lymph nodes. This could lead to greater confidence in pathologic staging and reliability of LND as a predictor of prognosis. Survival can improve due to increased awareness to perform a more thorough PLND.