Standaard lymfeklierdissectie bij blaascarcinoom: Significante verschillen in het aantal gerapporteerde lymfeklieren

Purpose: This study was performed to compare the nodal yield after histopathological examination of extended bilateral pelvic lymph node dissection (PLND) specimens for bladder cancer in 2 different hospitals. Surgery in both hospitals was performed by the same four staff urologists, using a standardized PLND template. Subsequently, we compared the survival outcomes between both groups. Materials and methods: All consecutive patients with bladder cancer who underwent a PLND in the period of 1-1-2007 until 31-12-2009 were included in this study. The specimens were sent to pathology in a minimum of 2 packages per side. The 2 pathology departments processed the specimens according to their institutional protocols. We compared the overall survival (OS), disease specific survival (DSS) and recurrence free survival (RFS) between both cohorts, using the Kaplan Meier method. Results: One hundred and seventy four patients were included, with a mean age of 62.7 years. In hospital A a mean total of 16 lymph nodes was found after dissection versus a mean of 28 reported lymph nodes in hospital B (p < 0.001). No significant differences were found in the number of tumour positive lymph nodes (p = 0.65). The mean lymph node density for hospital A was 9.3% and for hospital B 3.9% respectively (p = 0.056). The cumulative probabilities for 2-years 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. Conclusions: Despite equal anatomical clearance by the same experienced surgeons, we report a statistically significant difference between 2 pathology departments evaluating the number of lymph nodes after PLND for bladder cancer. Unless standardized methods have been agreed upon by pathologists, one should be cautious to use the number of reported lymph nodes as an indicator of quality of surgery and to use the lymph node density as prognostic factor.