Dose escalation for locally advanced pancreatic cancer: How high can we go?

Lauren E. Colbert, MD; Neal Rebueno, CMD; Shalini Moningi, MD; Sam Beddar, PhD; Gabriel O. Sawakuchi, PhD; Joseph M. Herman, MD; Albert C. Koong, MD, PhD; Prajnan Das, MD; Emma B. Holliday, MD; Eugene J. Koay, MD, PhD; Cullen M. Taniguchi, MD, PhD

Advances in Radiation Oncology (Oct 2018)

Dose escalation for locally advanced pancreatic cancer: How high can we go?

Lauren E. Colbert, MD,
Neal Rebueno, CMD,
Shalini Moningi, MD,
Sam Beddar, PhD,
Gabriel O. Sawakuchi, PhD,
Joseph M. Herman, MD,
Albert C. Koong, MD, PhD,
Prajnan Das, MD,
Emma B. Holliday, MD,
Eugene J. Koay, MD, PhD,
Cullen M. Taniguchi, MD, PhD

Affiliations

Lauren E. Colbert, MD: Department of Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, Texas
Neal Rebueno, CMD: Department of Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, Texas
Shalini Moningi, MD: Department of Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, Texas
Sam Beddar, PhD: Department of Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, Texas
Gabriel O. Sawakuchi, PhD: Department of Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, Texas
Joseph M. Herman, MD: Department of Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, Texas
Albert C. Koong, MD, PhD: Department of Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, Texas
Prajnan Das, MD: Department of Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, Texas
Emma B. Holliday, MD: Department of Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, Texas
Eugene J. Koay, MD, PhD: Department of Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, Texas
Cullen M. Taniguchi, MD, PhD: Corresponding author. The University of Texas, MD Anderson Cancer Center, Division of Radiation Oncology, 1515 Holcombe Blvd., Unit 1050, Houston, TX 77030-4000.; Department of Radiation Oncology, University of Texas, MD Anderson Cancer Center, Houston, Texas

Journal volume & issue: Vol. 3, no. 4
pp. 693 – 700

Abstract

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Purpose: There are limited treatment options for locally advanced, unresectable pancreatic cancer (LAPC) and no likelihood of cure without surgery. Radiation offers an option for local control, but radiation dose has previously been limited by nearby bowel toxicity. Advances in on-board imaging and treatment planning may allow for dose escalation not previously feasible and improve local control. In preparation for development of clinical trials of dose escalation in LAPC, we undertook a dosimetric study to determine the maximum possible dose escalation while maintaining known normal tissue constraints. Methods and Materials: Twenty patients treated at our institution with either SBRT or dose-escalated hypofractionated IMRT (DE-IMRT) were re-planned using dose escalated SBRT to 70 Gy in 5 fractions to the GTV and 40 Gy in 5 fractions to the PTV. Standard accepted organ at risk (OAR) constraints were used for planning. Descriptive statistics were generated for homogeneity, conformality, OAR's and GTV/PTV. Results: Mean iGTV coverage by 50 Gy was 91% (±0.07%), by 60 Gy was 61.3% (±0.08%) and by 70 Gy was 24.4% (±0.05%). Maximum PTV coverage by 70 Gy was 33%. Maximum PTV coverage by 60 Gy was 77.5%. The following organ at risk (OAR) constraints were achieved for 90% of generated plans: Duodenum V20 < 30 cc, V30 < 3 cc, V35 < 1 cc; Small Bowel V20 < 15 cc, V30 < 1 cc, V35 < 0.1 cc; Stomach V20 < 20 cc, V30 < 2 cc, V35 < 1 cc. V40 < 0.5 cc was achieved for all OAR. Conclusions: Dose escalation to 60 Gy is dosimetrically feasible with adequate GTV coverage. The identified constraints for OAR's will be used in ongoing clinical trials.

Published in Advances in Radiation Oncology

ISSN: 2452-1094 (Online)
Publisher: Elsevier
Country of publisher: United States
LCC subjects: Medicine: Medicine (General): Medical physics. Medical radiology. Nuclear medicine; Medicine: Internal medicine: Neoplasms. Tumors. Oncology. Including cancer and carcinogens
Website: http://www.journals.elsevier.com/advances-in-radiation-oncology/

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