Differences in histopathological evaluation of standard lymph node dissections result in differences in nodal count but not in survival.

OBJECTIVE: To analyse whether the reported differences in nodal yield at pelvic lymph node dissection (PLND) for bladder cancer, between two hospitals, are reflected in the survival rates. PATIENTS AND METHODS: We assessed follow-up data of all 174 patients (mean age: 62.7, median follow-up: 3 years) who underwent PLND between 1 January 2007 and 31 December 2009 at two different hospitals. PLND was performed according to a standardized template by the same urologists for comparable bladder cancer patients. Mean number of reported lymph nodes was 16 at hospital A versus 28 at hospital B. We compared the overall survival (OS), disease-specific survival (DSS) and recurrence-free survival (RFS) between both cohorts and performed a multivariate analysis.
RESULTS: The cumulative probability for 2-year OS, DSS and RFS for hospital A are 61, 64 and 54 %, versus 58, 58 and 53 % for hospital B, respectively. Kaplan-Meier survival curves did not reveal statistically significant differences between both groups (OS: p log-rank = 0.75, DSS: p log-rank = 0.56, and RFS: p log-rank = 0.80). Also after adjustment for pT stage and neoadjuvant chemotherapy, survival was not significantly different between hospital A and hospital B.
CONCLUSION: Despite differences in lymph node yield in PLND specimens, this study reveals no significant differences in survival outcomes between both hospitals. Standardized histopathological methods should be agreed upon by pathologists before integrating nodal yield and subsequent lymph node density as indicators of the quality of surgery and as prognostic factors.