Phase II Trial of Combined High-Dose-Rate Brachytherapy and External Beam Radiotherapy for Adenocarcinoma of the Prostate: Preliminary Results of RTOG 0321
Received 21 May 2009; received in revised form 29 July 2009; accepted 21 August 2009. published online 08 March 2010. Corrected Proof
Purpose
To estimate the rate of late Grade 3 or greater genitourinary (GU) and gastrointestinal (GI) adverse events (AEs) after treatment with external beam radiotherapy and prostate high-dose-rate (HDR) brachytherapy.
Methods and Materials
Each participating institution submitted computed tomography-based HDR brachytherapy dosimetry data electronically for credentialing and for each study patient. Patients with locally confined Stage T1c-T3b prostate cancer were eligible for the present study. All patients were treated with 45 Gy in 25 fractions using external beam radiotherapy and one HDR implant delivering 19 Gy in two fractions. All AEs were graded according to the Common Terminology Criteria for Adverse Events, version 3.0. Late GU/GI AEs were defined as those occurring >9 months from the start of the protocol treatment, in patients with ≥18 months of potential follow-up.
Results
A total of 129 patients from 14 institutions were enrolled in the present study. Of the 129 patients, 125 were eligible, and AE data were available for 112 patients at analysis. The pretreatment characteristics of the patients were as follows: Stage T1c-T2c, 91%; Stage T3a-T3b, 9%; prostate-specific antigen level ≤10 ng/mL, 70%; prostate-specific antigen level >10 but ≤20 ng/mL, 30%; and Gleason score 2–6, 10%; Gleason score 7, 72%; and Gleason score 8–10, 18%. At a median follow-up of 29.6 months, three acute and four late Grade 3 GU/GI AEs were reported. The estimated rate of late Grade 3-5 GU and GI AEs at 18 months was 2.56%.
Conclusion
This is the first prospective, multi-institutional trial of computed tomography-based HDR brachytherapy and external beam radiotherapy. The technique and doses used in the present study resulted in acceptable levels of AEs.
Reprint requests to: I.-Chow Joe Hsu, M.D., Department of Radiation Oncology, University of California, San Francisco, Helen Diller Family Comprehensive Cancer Center, 1600 Divisadero St., H1031, San Francisco, CA 94143-1708. Tel: (415) 353-7175; Fax: (415) 353-9883.
Supported by Grants RTOG U10 CA21661, CCOP U10 CA37422, Stat U10 CA32115 and U24 CA81647 from the National Cancer Institute, Rockville, MD.
This manuscript's contents are the sole responsibility of the authors and do not necessarily represent the official views of the National Cancer Institute.
ABSTRACT