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

Abstract

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 local-regional 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 follow-up 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.

• Authors: Sunil Krishnan, Awalpreet S Chadha, Yelin Suh, Hsiang-Chun Chen, Arvind Rao, Prajnan Das, Bruce D Minsky, Usama Mahmood, Marc E Delclos, Gabriel O Sawakuchi, Sam Beddar, Matthew H Katz, Jason B Fleming, Milind M Javle, Gauri R Varadhachary, Robert A Wolff, Christopher H Crane
• Journal: International journal of radiation oncology, biology, physics (Int J Radiat Oncol Biol Phys) Vol. 94 Issue 4 Pg. 755-65 (Mar 15 2016) ISSN: 1879-355X [Electronic] United States
• PMID: 26972648 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2016 Elsevier Inc. All rights reserved.

Topics

• Adult
• Aged
• Aged, 80 and over
• Antineoplastic Combined Chemotherapy Protocols (therapeutic use)
• Breath Holding
• Chemoradiotherapy (methods)
• Disease-Free Survival
• Dose Fractionation, Radiation
• Female
• Humans
• Induction Chemotherapy (methods)
• Male
• Middle Aged
• Neoplasm Recurrence, Local
• Pancreatic Neoplasms (diagnostic imaging, mortality, pathology, therapy)
• Radiography
• Radiotherapy Dosage
• Radiotherapy, Image-Guided
• Radiotherapy, Intensity-Modulated (methods)
• Retrospective Studies
• Treatment Outcome
• Tumor Burden (radiation effects)