Effect of Chemoradiation on Survival of Resected Pancreatic Ductal Adenocarcinoma with Close or Positive Margins

Abstract

Long-term (>5y) survival of pancreatic carcinoma has historically been poor. After potentially curative pancreatoduodenectomy, tumor size, lymph node status, histologic grade, and margin status have been shown to be the best predictors of survival after surgery. We performed a retrospective analysis of a prospectively collected cohort of patients to ascertain the effect of chemoradiation on overall survival after a resection with either close or positive margins. We analyzed 123 patients with histologically proven pancreatic ductal adenocarcinoma that underwent either a pancreatoduodenectomy (PW) or pylorus preserving pancreatoduodenectomy (PPW) between 1996-2007 with a minimum of 12 months followup. All patients that received radiation also received chemotherapy. The median dose of radiation was 5040cGy. Of the 123 patients that underwent resection, 67 underwent PPW; 56 underwent PW. Forty-two patients were classified with involved margins: 30 had a true positive margin, defined as tumor at the inked margin; 12 had a close (within 1mm) margin. The radial peri-pancreatic margin was the most commonly close/positive margin involved (n = 23), followed by 13 patients with a pancreatic neck margin. The other close/positive margins were: portal vein (n = 1), superior mesenteric artery (n = 1), and multiple positive margins (n = 4). Post-operative chemoradiation was received in 17 of the 42 (40%). Median overall survival (MS) in the entire cohort was 15.1 months. MS in the margin negative group (n = 81, 66%) was 18.8. MS in the entire margin close/positive margin group (n = 42, 34%) was 9.9 months. MS in the margin close/positive group that received no additional multi-modality therapy was 7.6 months. In the margin close/positive patients that received post-operative chemoradiation, the MS improved to 14.3 months. Eight of the close/positive margin patients received chemotherapy without radiation; MS in this cohort was 7.7 months. Despite resection with close or positive margins which portends a poorer prognosis, MS can be improved with the addition of chemoradiation. Our cohort suggests an added benefit of radiation as MS with chemotherapy but without radiation is similar to MS without any adjuvant therapy. However, even with the addition of multi-modality therapy, MS remains poor.