Radiation as a Single-Modality Treatment in Localized Pancreatic Cancer.

Locally advanced pancreatic cancer (LAPC) is managed with multimodality therapy. We aim to evaluate the outcome of single-modality radiation therapy for LAPC. Locally advanced pancreatic cancer patients were identified between 2004 and 2013 using the National Cancer Database excluding patients who received chemotherapy or surgery. A total of 6590 patients were included. The mean age was 73.5 (range, 28-90) years, 83.2% were white, and 54.4% were female. Tumors of 4 cm or greater (>T3 stage) accounted for 52.7%. The median radiation dose was 39.6 Gy. Stereotactic body radiation (SBRT) delivered to 64 patients and external-beam/intensity modulated radiotherapy in 416 patients. Radiation therapy was associated with improved overall survival (OS) compared with no treatment in univariate and multivariable analyses. The medians OS for patients who received SBRT, external-beam/intensity modulated radiotherapy, or no radiation were 8.6, 6.7, and 3.4 months, respectively (P < 0.001). There is a significant difference in 12-month OS for the SBRT cohort (31.9%; 95% confidence interval [CI], 20.9%-43.5%) compared with patients who received no radiation (15.1%; 95% CI, 14.2%-16.0%), and on multivariable analysis (hazard ratio, 0.50; 95% CI, 0.38-0.65; P < 0.001). The current study suggests potential benefit for radiation therapy alone in comparison with no treatment in LAPC.