Prognostic relevance of extracapsular lymph node involvement in pancreatic ductal adenocarcinoma.

BACKGROUND: In several malignancies extracapsular lymph node involvement (ECLNI) identifies a subgroup of patients with worse prognosis but no data are available on its significance in pancreatic ductal adenocarcinoma (PDAC). The aim of our study was to assess the prognostic relevance of ECLNI in resectable PDAC. METHODS: A retrospective analysis was performed of 137 consecutive pancreatic resections for PDAC. Two investigators blinded for survival data systematically reviewed all pathological data. Survival curves were estimated using the Kaplan-Meier method. Multivariable Cox regression models were used to identify predictors of disease-free survival (DFS) and overall survival (OS). The median follow-up after surgery was 19 months. RESULTS: ECLNI was identified in 59 of 99 node-positive patients. The median DFS in patients with ECLNI vs. intracapsular LNI (ICLNI) was 6.8 vs. 12.0 months, respectively (P=.027). The median OS in patients with ECLNI vs. ICLNI was 16.1 and 21.8 months, respectively (P=.098). On multivariable analysis extracapsular lymph node ratio (ECLNR) was identified as an independent predictor of OS (P=.003). In patients with ECLNI, both OS and DFS were improved after adjuvant chemoradiation compared with those who did not receive adjuvant treatment (P=.01). CONCLUSIONS: Extracapsular lymph node ratio is an independent predictor of survival in patients with PDAC. Patients with ECLNI from pancreatic cancer seem to benefit from adjuvant chemoradiation but not from chemotherapy alone.