Original Article

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

William A. Hall, Lauren E. Colbert, Dana Nickleach, Jeffrey Switchenko, Yuan Liu, Theresa Gillespie, Joseph Lipscomb, Claire Hardy, David A. Kooby, Roshan S. Prabhu, John Kauh, Jerome C. Landry


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.

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