Phase II trial of combined high-dose-rate brachytherapy and external beam radiotherapy for adenocarcinoma of the prostate: preliminary results of RTOG 0321.
OBJECTIVE
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
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%.


CONCLUSIONS
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.
Hsu
I-Chow
IC
University of California, San Francisco, Helen Diller Family Comprehensive Cancer Center, San Francisco, CA 94143-1708, USA. ihsu@radonc.ucsf.edu
Bae
Kyounghwa
K
Shinohara
Katsuto
K
Pouliot
Jean
J
Purdy
James
J
Ibbott
Geoffrey
G
Speight
Joycelyn
J
Vigneault
Eric
E
Ivker
Robert
R
Sandler
Howard
H
D000230:Adenocarcinoma / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods* / Q000592:standards; D003556:Cystitis / Q000209:etiology; D007172:Erectile Dysfunction / Q000209:etiology; D041981:Gastrointestinal Tract / Q000528:radiation effects*; D006801:Humans; D007668:Kidney / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology* / Q000532:radiotherapy; D011786:Quality Control; D011878:Radiotherapy / Q000009:adverse effects / Q000379:methods / Q000592:standards; D011879:Radiotherapy Dosage; D012007:Rectum / Q000473:pathology / Q000528:radiation effects; D001743:Urinary Bladder / Q000473:pathology / Q000528:radiation effects; D014555:Urination Disorders / Q000209:etiology; D014566:Urogenital System / Q000528:radiation effects*
D017430:Prostate-Specific Antigen