Radiation therapy is associated with improved survival in patients with pancreatic adenocarcinoma: Results of a study from the surveillance, epidemiology, and end results (SEER) registry data

BACKGROUND. The role of adjuvant radiation therapy in pancreatic cancer is controversial. For the current study, the authors evaluated the effect of preoperative and postoperative radiation therapy on survival in patients with pancreatic adenocarcinoma. METHODS. The analysis included 3008 patients who were reported to the Surveillance, Epidemiology, and End Results registry of the National Cancer Institute from 1988 to 2002 who had adenocarcinoma of the pancreas and who underwent cancer-directed surgery. A retrospective analysis of overall survival and cancer-specific survival for these patients was performed using the Kaplan-Meier method. Comparative risks of mortality were evaluated by using multivariate-adjusted Cox regression models. RESULTS. Of 3008 patients, 1267 (42%) received radiation therapy. Overall survival improved significantly in patients who received radiation therapy, with a median survival of 17 months and a 5-year overall survival rate of 13% in patients who received radiation compared with 12 months and 9.7%, respectively, for patients who did not receive radiation therapy (P < .0001). On multivariate analysis, radiation therapy was associated with improvement in overall survival in patients who had direct extension beyond the pancreas and/or regional lymph node involvement (P < .01) but not in patients with T1-T2N0M0 disease (P > .05). Radiation therapy was associated with improvement in cause-specific survival in patients who had regional lymph node involvement (P < .02) but not in patients who had T1-2N0M0 disease or direct extension beyond the pancreas without lymph node involvement (P > .05). Differences in overall and cause-specific survival among patients who received preoperative versus postoperative radiation therapy did not reach statistical significance. CONCLUSIONS. Radiation therapy was associated with improved survival compared with cancer-directed surgery without radiation in patients with adenocarcinoma of the pancreas.