Focal Radiation Therapy Dose Escalation Improves Overall Survival in Locally Advanced Pancreatic Cancer Patients Receiving Induction Chemotherapy and Consolidative Chemoradiation

Purpose: To review outcomes of locally advanced pancreatic cancer (LAPC) patients treated with dose-escalated intensity modulated radiation therapy (IMRT) with curative intent. Methods and Materials: A total of 200 patients with LAPC were treated with induction chemotherapy followed by chemoradiation between 2006 and 2014. Of these, 47 (24%) having tumors >1 cm from the luminal organs were selected for dose-escalated IMRT (biologically effective dose [BED] >70 Gy) using a simultaneous integrated boost technique, inspiration breath hold, and computed tomographic image guidance. Fractionation was optimized for coverage of gross tumor and luminal organ sparing. A 2-to 5-mm margin around the gross tumor volume was treated using a simultaneous integrated boost with a microscopic dose. Overall survival (OS), recurrence-free survival (RFS), local-regional and distant RFS, and time to localregional and distant recurrence, calculated from start of chemoradiation, were the outcomes of interest. Results: Median radiation dose was 50.4 Gy (BED = 59.47 Gy) with a concurrent capecitabine-based (86%) regimen. Patients who received BED > 70 Gy had a superior OS (17.8 vs 15.0 months, P=. 03), which was preserved throughout the followup period, with estimated OS rates at 2 years of 36% versus 19% and at 3 years of 31% versus 9% along with improved local-regional RFS (10.2 vs 6.2 months, P=. 05) as compared with those receiving BED <= 70 Gy. Degree of gross tumor volume coverage did not seem to affect outcomes. No additional toxicity was observed in the high-dose group. Higher dose (BED) was the only predictor of improved OS on multivariate analysis. Conclusion: Radiation dose escalation during consolidative chemoradiation therapy after induction chemotherapy for LAPC patients improves OS and local-regional RFS. (c) 2016 Elsevier Inc. All rights reserved.