Effect of radiotherapy on survival in patients with resected non-pancreatic periampullary malignancies: Analysis using the surveillance, epidemiology, and end results (SEER) registry data

5060 Purpose: Patients with resected non-pancreatic periampullary malignancies often undergo adjuvant radiotherapy, but evidence from prospective studies is lacking. We evaluated the effect of radiotherapy on survival in patients with non-metastatic non-pancreatic periampullary cancers who underwent cancer directed surgery using the Surveillance, Epidemiology, and End Results (SEER) registry. Methods: A total of 1564 patients with resected carcinoma of the ampulla (C24.0), extrahepatic bile duct (C24.1), and duodenum (C17.0) were identified from the SEER registry between1988 and 2003. Periampullary lymphoma, sarcoma, carcinoid, and endocrinoma were excluded. Overall survival (OS) and cancer-specific survival (CSS) were analyzed by the Kaplan-Meier method. Multivariate analysis was performed with Cox regression. Results: Radiotherapy was administered in 412 (26%) of these patients; 94% in the adjuvant setting. The proportions of patients who received radiotherapy were as follows: 181/789 (22.9%) for ampullary primary, 157/422 (37.2%) for extrahepatic bile duct cancer, and 73/353 (21.0%) for cancer of the duodenum. Patients who received radiotherapy were more likely to have higher stage disease, nodal involvement, poorly differentiated grade, but had a younger age at diagnosis. For all patients, survival analysis demonstrated that radiotherapy did not improve OS when compared to no radiotherapy (2-year and 5-year OS: 51% vs. 59% and 28% vs. 38%, respectively, p=0.062) and adversely affected CSS (2-year and 5-year CSS: 63% vs. 73% and 42% vs. 56%, respectively, p= 0.0003). Multivariate analysis showed that radiotherapy did not affect OS (HR=0.96, 95% CI = 0.82-1.13) or CSS (HR=1.02, 95% CI = 0.84-1.25). Higher T stage, nodal involvement, and age greater than 60 were associated with poorer OS and CSS. In addition to these factors, poorly differentiated grade was also significantly associated with decreased CSS. Multivariate analysis by primary sites showed that radiotherapy improved OS but not CSS in patients with ampullary cancer; radiotherapy had no significant effect on OS or CSS in patients with cancers of the extrahepatic bile duct or duodenum. Conclusion: Radiotherapy is not associated with improved OS or CSS in patients with resected non-pancreatic periampullary malignancies in this population-based registry. Patients with adverse clinicopathological characteristics and younger age at diagnosis were more likely to receive adjuvant radiotherapy.