Stereotactic body radiotherapy for pancreatic cancer: Analysis of toxicity.

436 Background: Pancreatic ductal adenocarcinoma (PDAC) carries a poor prognosis, with significant morbidity and mortality from local progression. Radiotherapy can be administered for local control, with stereotactic body radiotherapy (SBRT) increasingly being utilized. We aim to compare the toxicity of SBRT with intensity-modulated radiotherapy (IMRT) in this setting. Methods: A retrospective analysis of patients with PDAC receiving IMRT or SBRT at our institution between April 2011 and November 2015 was performed. 81 patients were identified. Clinical notes were reviewed for treatment details and acute and late toxicities. Late toxicity data was available for 62 patients. Toxicity was assessed using Common Terminology Criteria for Adverse Events version 4.0. Radiology reports were reviewed to assess for the presence of recurrence and/or progression. Results: Median follow-up from RT was 29 months (95% CI 22-36 months), and median survival from RT was 25 months (95% CI 22-34 months). IMRT patients received 37.5-54 Gy in 15-30 fractions. SRBT patients received 19.8-39.6 Gy in 3-6 fractions. 45% of IMRT and 29% of SBRT patients had local failure (p = 0.1329). IMRT patients were significantly more likely to have Grade ≥2 acute gastrointestinal (GI) toxicity than SBRT patients (RR 1.70; 95% CI 0.98-2.96, p = 0.0489), although one SBRT patient had to have treatment stopped due to extrahepatic stricture. There were no significant differences in late GI toxicity (67% Grade 2 or higher vs. 57%, respectively, p = 0.4244), although one IMRT patient died due to late GI bleeding.IMRT patients were more likely to lose weight during RT(Median -0.03% vs. -0.004%, p = 0.0001) and have moreEmergency Department (ED) visits after RT (Range 0-8 vs. 0-3, p = 0.0019). There were no significant differences in dermatitis, fatigue, or hematologic toxicity. Conclusions: Patients with locally advanced PDAC treated with IMRT versus SBRT had significantly more acute gastrointestinal toxicity, median weight loss, and ED visits after RT, but no significant differences in late gastrointestinal toxicity, dermatitis, fatigue, or hematologic toxicity. SBRT is a relatively tolerable and more convenient alternative for patients with pancreatic cancer. </jats:p