Pancreatic Stereotactic Body Radiation Therapy With or Without Hypofractionated Elective Nodal Irradiation.

PURPOSE: Pancreatic stereotactic body radiation therapy (SBRT) is limited to gross tumor without elective coverage for subclinical disease. Given a better understanding of recurrence patterns, we hypothesized that the addition of elective nodal irradiation (ENI) to pancreatic SBRT would be tolerable and would decrease locoregional progression. METHODS AND MATERIALS: We conducted a retrospective 1:2 propensity-matched cohort study to compare toxicity and locoregional progression among patients treated with pancreatic SBRT with or without ENI. In the SBRT + ENI cohort, an elective target volume was delineated per Radiation Therapy Oncology Group guidelines and treated to 25 Gy in 5 fractions alongside 40 Gy in 5 fractions to gross disease. The primary outcome was the cumulative incidence of locoregional progression, with death as a competing risk. RESULTS: Among 135 candidate controls treated with SBRT alone, 100 were propensity-matched to 50 patients treated with SBRT + ENI. All patients completed SBRT. Median potential radiographic follow-up was 28 months. The incidence of late and serious acute toxicity was similar between matched cohorts. However, SBRT + ENI was associated with a statistically significant increase in acute grade 1 to 2 nausea (60% vs 20%, P < .001). The 24-month cumulative incidences of locoregional progression with and without ENI were 22.6% (95% confidence interval [CI], 10.0%-35.1%) versus 44.6% (95% CI, 34.8%-54.4%; multivariable-adjusted hazard ratio, 0.39; 95% CI, 0.18-0.87; P = .021). This was stable in sensitivity analyses of uniform prescription dose, multiagent chemotherapy, and resectability. There were fewer peripancreatic (0% vs 7%), porta hepatis (2% vs 7%), and peri-aortic/aortocaval (5% vs 12%) recurrences after SBRT + ENI, but no difference in survival. CONCLUSIONS: Pancreatic SBRT + ENI was tolerable and did not increase late or serious acute toxicity relative to a matched cohort undergoing SBRT alone, but did increase acute grade 1 to 2 nausea. The addition of ENI to SBRT was associated with decreased locoregional progression but not improved survival. Further studies are warranted to determine whether ENI offers meaningful benefit.

Intensified systemic therapy and stereotactic ablative radiotherapy dose for patients with unresectable pancreatic adenocarcinoma.

PURPOSE: We aimed to report the long-term impact of modern chemotherapy and SABR dose regimens on oncologic outcomes of unresectable pancreatic adenocarcinoma (PA). MATERIALS AND METHODS: We reviewed the treatment characteristics and outcomes of all patients who received multi-fraction SABR for unresectable PA between February 2007 and August 2018 at our institution. Time-to-events were calculated from date of diagnosis treating death as a competing risk. RESULTS: A total of 149 patients were identified. Median follow-up was 15 months (range: 5-47). Median SABR dose was 33 Gy (range: 20-45) delivered in 5 fractions in 143 patients, and 3 or 6 fractions in 6 patients. 107 patients (72%) received gemcitabine-based chemotherapy while 31 (21%) received modified FOLFIRINOX (mFFX). Median OS was 16 months (95% CI, 14-17), with a 1-year cumulative incidence of LF of 14%. The combination of SABR doses ≥40 Gy and mFFX (n = 21) showed a superior PFS and OS to the use of GEM-based chemotherapy with <40 Gy SABR doses (median PFS: 14 vs. 10 months, HR: 0.46, 95% CI: 0.29-0.71, P = 0.003; median OS: 24 vs. 14 months, HR: 0.36, 95% CI: 0.22-0.59, P = 0.002), with 1-year PFS and OS of 67% and 90% compared to 35% and 59% for those who received GEM-based chemotherapy with <40 Gy SABR doses, respectively. CONCLUSIONS: The use of mFFX and a SABR dose ≥40 Gy in 5 fractions may be superior compared to regimens that utilize gemcitabine-based chemotherapy or SABR doses <40 Gy.

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

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.