The influence of radiation therapy dose escalation on overall survival in unresectable pancreatic adenocarcinoma

• Authors: William A. Hall, Emory University; Lauren E. Colbert, Emory University; Dana Nickleach, Emory University; Jeffrey M. Switchenko, Emory University; Yuan Liu, Emory University; Theresa Wicklin Gillespie, Emory University; Joseph Lipscomb, Atlanta Veterans Affairs Medical Center; Claire Hardy, Emory University; David A Kooby, Emory University; Roshan S. Prabhu, Emory University; John Kauh, Emory University; Jerome C Landry, Emory University
• Journal Title: Journal of Gastrointestinal Oncology
• Volume: Volume 5, Number 2
• Publisher: Pioneer Bioscience Publishing Company | 2014-04, Pages 77-85
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.3978/j.issn.2078-6891.2014.001
• Subjects: Health Sciences, Oncology; Health Sciences, Radiology
• Keywords: Radiation dose escalation pancreatic cancer; radiation dose escalation in pancreatic adenocarcinoma (PAC); unresectable pancreatic cancer; PAC and radiation therapy (RT); RT dose in unresectable pancreatic cancer; PAC and intensity modulated radiation therapy (IMRT); dose response pancreatic cancer

Abstract

Purpose Radiation therapy (RT) dose escalation in unresectable pancreatic adenocarcinoma (PAC) remains investigational. We examined the association between total RT dose and overall survival (OS) in patients with unresectable PAC. Methods and materials National cancer data base (NCDB) data were obtained for patients who underwent definitive chemotherapy and RT (chemo-RT) for unresectable PAC. Univariate (UV) and multivariate (MV) survival analysis were performed along with Kaplan-Meier (KM) estimates for incremental RT dose levels. Results A total of 977 analyzable patients met inclusion criteria. Median tumor size was 4.0 cm (0.3-40 cm) and median RT dose was 45 Gy. Median OS was 10 months (95% CI, 9-10 months). On MV analysis RT dose <30 Gy [HR, 2.38 (95% CI, 1.85-3.07); P<0.001] and RT dose ≥30 to <40 Gy [HR, 1.41 (95% CI, 1.04-1.91); P=0.026] were associated with lower OS when compared with dose ≥55 Gy. Patients receiving RT doses from 40 to <45, 45 to <50, 50 to <55, and ≥55 Gy did not differ in OS. Conclusions Lack of benefit to OS with conventionally delivered RT above 40 Gy is shown. Optimal RT dose escalation methods in unresectable PAC remain an important subject for investigation in prospective clinical trials.