Does adjuvant radiation provide any survival benefit after an R1 resections for pancreatic cancer?

Abstract

The benefit of adding external beam radiation to adjuvant chemotherapy in patients that have undergone a margin positive resection for early stage, pancreatic ductal adenocarcinoma has not been determined definitively. The National Cancer Data Base was queried to evaluate the utility of adjuvant radiation in patients with pathologic stage I-II pancreatic ductal adenocarcinoma who underwent upfront pancreatoduodenectomy with a positive margin (margin positive resection) between 2004 and 2013. In the study, 1,392 patients met inclusion criteria, of whom 263 (18.9%) were lymph node-negative (pathologic stages IA, IB, IIA) and 1,129 (81.1%) were node-positive (pathologic stage IIB); 938 (67.4%) patients received adjuvant radiation and chemotherapy, while 454 (32.6%) received adjuvant chemotherapy alone. Cox modeling stratified by nodal status demonstrated the benefit of radiation to be statistically significant only in node positive patients (hazard ratio 0.81, 95% confidence interval, 0.71-0.93). Node-positive patients receiving adjuvant radiation and chemotherapy had an adjusted median survival of 17.5 months vs 15.2 months for those receiving adjuvant chemotherapy alone (P=.003). In patients who had negative nodes, there was no difference in overall survival with radiation (22.5 vs 23.6 months, P=.511). Addition of radiation to adjuvant chemotherapy after a margin positive resection confers a survival benefit albeit limited (about 2 months) in patients with node-positive pancreatic head cancer. (Surgery 2017;160:XXX-XXX.).