The Utility of Stereotactic Body Radiotherapy for Palliation of Metastatic Pancreatic Adenocarcinoma

Abstract Purpose To report the outcome of stereotactic ablative radiotherapy (SABR) to the primary tumor for patients with metastatic pancreatic cancer. Materials and Methods We examined the records of patients with metastatic pancreatic cancer treated with SABR to the primary tumor between 2002 and 2018. Toxicities were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03. Pain intensity pre- and post-SABR was scored according to the Stanford Pain Scale as reported by the patient. Time-to-events were calculated from the date of end of SABR delivery. Results In total, 27 patients were identified that met the inclusion criteria. Seventeen (63%) patients received single fraction SABR with a median dose of 25 Gy (range: 12.5-25), while 10 (37%) patients were treated in 5 fractions with a median dose of 33 Gy (range: 25-40). Prior to the start of SABR, 17 (63%) patients reported having abdominal pain, with a median intensity of 5 in the 0 to 10 pain scale (range: 1-9), 11 (41%) of them necessitating continuous opioid use. The median follow-up was of 6 months (range: 0-18). Median overall survival was of 7 months (95% CI, 3-10), with a cumulative incidence of local failures at 1 year of 25% (95% CI, 10-44). After SABR, there was a significant reduction in the mean intensity of pain (P = 0.01), and a 46% relative reduction in continuous opioid use. Only two patients (7%) presented a grade 3 toxicity that could be attributed to treatment. Conclusion In this small series, SABR demonstrated to be a safe and effective option for the local palliation of metastatic pancreatic cancer, with measurable improvements in abdominal pain and opioid necessity.