Improved survival with radiation therapy in early pancreatic adenocarcinoma

Abstract

15036 Background: Although chemoradiation is often used following pancreatic cancer resection, recent studies have questioned the role of radiation therapy in this setting. The objective of this study was to determine the effect of adjuvant radiation therapy following pancreatectomy in patients with node-negative (N0) pancreatic cancer. Methods: The Surveillance, Epidemiology, and End Results (SEER) registry was used to identify patients with N0 pancreatic adenocarcinoma who had undergone curative-intent resection between 1988–2003. Kaplan-Meier survival curves were constructed to compare overall survival between patients ± adjuvant radiation therapy. Multivariate Cox regression analysis was performed to determine the prognostic significance of radiation therapy when additional clinicopathologic factors were assessed. The analysis also examined the potential treatment selection bias of patients with survival <3 months. Results: Query of the SEER database identified 2342 surgical patients with N0 disease. The median survival for these patients was 18 months. 889 (60.1%) patients were treated with radiation. There was no difference in gender or grade between radiation and non-radiation groups; however, radiation patients were younger (63 vs. 67 years, p<0.001) and had a greater proportion of T3 lesions (p=0.002). Radiation patients had significantly improved survival compared to non-radiation patients (20.0 vs. 15.0 months, p<0.001). On multivariate analysis, radiation therapy (HR 0.72, p<0.001), age, grade, T-stage, and tumor location were independent predictors of survival. When patients with survival <3 months were excluded from analysis, no difference in survival between radiation and non- radiation was noted (20.0 vs. 19.0 months, p=0.096). However, on subset analysis, patients with T3 tumors demonstrated improved survival with the addition of radiation (24.0 vs 16.0 months, p=0.002) and on multivariate analysis radiation therapy was an independent predictor of improved overall survival (HR 0.87, p=0.027). Conclusions: Radiation treatment is associated with improved survival in operable N0 pancreatic cancer and its use should be considered in patients with early stage N0 disease. The greatest impact of radiation therapy use appears to occur with T3 tumors. No significant financial relationships to disclose.