Postoperative Radiotherapy for Pancreatic Cancer with Microscopically-positive Resection Margin

Aim: To analyze the outcomes in pancreatic cancer (PC) cases with a microscopically-positive resection margin (R1 resection) treated with postoperative radiotherapy (PORT). Patients and Methods: We retrospectively analyzed the outcomes in 62 patients who received PORT for PC with R1 resection between 2001 and 2012. All patients received three-dimensional conformal radiotherapy. Concurrent chemotherapy was administered to 58 patients. Results: The median follow-up was 20.1 months. The median survival was 22.0 months and the 3-year overall survival rate was 25%. The 3-year disease-free survival and local recurrence-free survival rates were 12% and 54%, respectively. Local recurrence occurred in 23 patients (44%), distant failure in 45 (87%), and both in 16 (31%). By multivariate analysis, the postoperative cancer antigen 19-9 (CA19-9) level and adjuvant chemotherapy were independent prognostic factors for survival. Conclusion: PORT is associated with a relatively favorable survival outcome in PC with R1 resection. Chemotherapy and postoperative CA19-9 level were significant prognostic factors for survival.