Extranodal extension in N1-adenocarcinoma of the pancreas and papilla of Vater: a systematic review and meta-analysis of its prognostic significance

The aim of the study was to investigate the prognostic role of extranodal extension (ENE) of lymph node metastasis in adenocarcinoma of the pancreas (PDAC) and papilla [cancer of the papilla of Vater (CPV)]. A PubMed and SCOPUS search from database inception until 5 January 2015 without language restrictions was conducted. Eligible were prospective studies reporting data on prognostic parameters in individuals with PDAC and/or CPV, comparing participants with the presence of ENE (ENE+) with those with intranodal extension (ENE-). Data were summarized using risk ratios for number of deaths/recurrences and hazard ratios for time-dependent risk related to ENE+, adjusted for potential confounders. ENE was found to be very common in these tumors (up to about 60% in both N1-PDAC and CPV), leading to a significant increased risk for all-cause mortality [risk ratio=1.20; 95% confidence interval (CI): 1.06-1.35, P=0.003, I-2=44%; hazard ratio=1.415, 95% CI: 1.215-1.650, P<0.0001, I-2=0%] and recurrence of disease (risk ratio=1.20, 95% CI: 1.03-1.40, P=0.02, I-2=0%). On the basis of our results, in PDAC and CPV, ENE should be considered mandatorily from the gross sampling and pathology report to the oncologic staging and therapeutic approach.