The Utility of Stereotactic Ablative Radiation Therapy for Palliation of Metastatic Pancreatic Adenocarcinoma.

ABSTRACT

PURPOSE: Our purpose was to report the outcome of stereotactic ablative radiation therapy (SABR) to the primary tumor for patients with metastatic pancreatic cancer. METHODS AND MATERIALS 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), and 10 (37%) patients were treated in 5 fractions with a median dose of 33 Gy (range, 25-40). Before 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 needing continuous opioid use. The median follow-up was 6 months (range, 0-18). Median overall survival was 7 months (95% confidence interval, 3-10), with a cumulative incidence of local failures at 1 year of 25% (95% confidence interval, 10-44). After SABR, there was a significant reduction in the mean intensity of pain (P = .01), and a 46% relative reduction in continuous opioid use. Only 2 patients (7%) presented a grade 3 toxicity that could be attributed to treatment. CONCLUSIONS: In this small series, SABR was a safe and effective option for the local palliation of metastatic pancreatic cancer, with measurable improvements in abdominal pain and the need for opioids.