A planning study of focal dose escalations to multiparametric MRI-defined dominant intraprostatic lesions in prostate proton radiation therapy

• Type of Material: Article
• Authors: Tonghe Wang, Emory University; Jun Zhou, Emory University; Sibo Tian, Emory University; Yinan Wang, Emory University; Pretesh Patel, Emory University; Ashesh Jani, Emory University; Katja Langen, Emory University; Walter J Curran, Emory University; Tian Liu, Emory University; Xiaofeng Yang, Emory University
• Language: English
• Date: 2020-01-01
• Publisher: BRITISH INST RADIOLOGY
• Publication Version: Final Published Version
• Copyright Statement: © 2020 The Authors
• Final Published Version (URL): http://dx.doi.org/10.1259/bjr.20190845
• Title of Journal or Parent Work: BRITISH JOURNAL OF RADIOLOGY
• Volume: 93
• Issue: 1107
• Start Page: 20190845
• End Page: 20190845
• Grant/Funding Information: This research was supported in part by the National Cancer Institute of the National Institutes of Health under Award Number R01CA215718 (XY), the Department of Defense (DoD) Prostate Cancer Research Program (PCRP) Award DoD W81XWH-17-1-0438 (TL) and W81XWH-17-1-0439 (AJ) and Dunwoody Golf Club Prostate Cancer Research Award (XY), a philanthropic award provided by the Winship Cancer Institute of Emory University.
• Keywords: Life Sciences & Biomedicine; BOOST; DISTRIBUTIONS; Radiology, Nuclear Medicine & Medical Imaging; CANCER; BRACHYTHERAPY; TOMOTHERAPY; URETHRAL STRICTURES; MONOTHERAPY; ANDROGEN DEPRIVATION; RADIOTHERAPY; COMPLICATION PROBABILITY; Science & Technology
• Research Categories: Biology, Radiation; Health Sciences, Oncology

Abstract

Objectives: The purpose of this study is to investigate the dosimetric effect and clinical impact of delivering a focal radiotherapy boost dose to multiparametric MRI (mp-MRI)- defined dominant intraprostatic lesions (DILs) in prostate cancer using proton therapy. Methods: We retrospectively investigated 36 patients with pre-treatment mp-MRI and CT images who were treated using pencil beam scanning (PBS) proton radiation therapy to the whole prostate. DILs were contoured on co-registered mp-MRIs. Simultaneous integrated boost (SIB) plans using intensity-modulated proton therapy (IMPT) were created based on conventional whole-prostate- irradiation for each patient and optimized with additional DIL coverage goals and urethral constraints. DIL dose coverage and organ-at- risk (OAR) sparing were compared between conventional and SIB plans. Tumor control probability (TCP) and normal tissue complication probability (NTCP) were estimated to evaluate the clinical impact of the SIB plans. Results: Optimized SIB plans significantly escalated the dose to DILs while meeting OAR constraints. SIB plans were able to achieve 125, 150 and 175% of prescription dose coverage in 74, 54 and 17% of 36 patients, respectively. This was modeled to result in an increase in DIL TCP by 7.3-13.3% depending on -/- and DIL risk level. Conclusion: The proposed mp-MRI- guided DIL boost using proton radiation therapy is feasible without violating OAR constraints and demonstrates a potential clinical benefit by improving DIL TCP. This retrospective study suggested the use of IMPT-based DIL SIB may represent a strategy to improve tumor control.