Radiotherapy in locally advanced pancreatic cancer: SEER experience.

Abstract

364 Background: Pancreatic cancer is the fourth most common cause of cancer deaths in the US. Despite the fact that the radiotherapy in addition to chemotherapy is frequently employed, the role of radiation therapy in the treatment of locally advanced pancreatic cancer (LAPC) remains controversial. The majority of the data evaluating the efficacy of this approach is derived from small randomized trials. Methods: The Surveillance, Epidemiology and End Results (SEER) registry dataset from 2004-2011 was queried to identify patients with locally advanced pancreatic adenocarcinoma. Pts with survival <2 months, unknown radiation status and those who received post-operative radiation were excluded. Multivariate analysis of prognostic factors related to survival was performed using a Cox proportional hazard regression model. Results: We identified 4,460 patients that met the inclusion criteria; 59% of pts received radiation and 41% did not. The two groups were similar with respect to gender, race and tumor differentiation. Pts in the radiation group were younger (ages<65: 49% vs. 38%), had smaller tumor size (largest dimension <4.5 cm: 80% vs. 75%), lesser lymph node involvement (33% vs. 36%) and lower rate of surgical resection (4% vs. 9%). Radiation treatment, age, tumor grade and surgical resection were significantly associated with survival on univariate analysis. Patients who received radiation therapy had better survival (median OS: 11 vs. 7 months; HR: 0.77; 95% CI 0.69-0.78). On the multivariate analysis, radiation was independently associated with improved survival (Table). Conclusions: In this population-based registry, radiation therapy was associated with improved survival in patients with LAPC in both univariate and multivariate analysis. Larger randomized trials are needed to confirm these findings. The optimal schedule and type of radiation therapy remains unknown. [Table: see text]