Prophylactic breast irradiation with a single dose of electron beam radiotherapy (10 Gy) significantly reduces the incidence of bicalutamide-induced gynecomastia.
OBJECTIVE
To evaluate the efficacy and tolerability of prophylactic breast irradiation in reducing the incidence and severity of bicalutamide-induced gynecomastia and breast pain.


METHODS
In all, 106 men with prostate cancer (T1b-T4/Nx/M0) and no current gynecomastia/breast pain were enrolled in this randomized, sham-controlled, double-blind, parallel-group multicenter trial. Patients received either a single dose of electron beam radiotherapy (10 Gy) or sham radiotherapy. Bicalutamide (Casodex) 150 mg/day was administered for 12 months from the day of radiotherapy. Every 3 months, patients underwent physical examination and questioning about gynecomastia and breast pain.


RESULTS
The incidence of investigator-assessed gynecomastia was significantly lower with radiotherapy vs. sham radiotherapy (52% vs. 85%; odds ratio [OR], 0.13; 95% confidence interval [CI], 0.04, 0.38; p < 0.001); direct questioning showed similar results. Fewer radiotherapy patients had >/=5 cm gynecomastia (measured by calipers; 11.5% vs. 50.0% for sham radiotherapy), and fewer cases were moderate-to-severe in intensity (21% vs. 48%). Similar proportions of radiotherapy and sham radiotherapy patients experienced breast pain (83% vs. 91%; OR, 0.25; 95% CI, 0.05, 1.27; p = 0.221); patients receiving radiotherapy experienced some reduction in its severity (OR, 0.44; 95% CI, 0.20, 0.97; p = 0.0429).


CONCLUSIONS
Prophylactic breast irradiation is an effective and well-tolerated strategy for prevention of bicalutamide-induced gynecomastia.
Tyrrell
Christopher J
CJ
Oncology Research Unit, Plymouth Oncology Centre, Plymouth, United Kingdom.
Payne
Heather
H
Tammela
Teuvo L J
TL
Bakke
August
A
Lodding
Pär
P
Goedhals
Louis
L
Van Erps
Peter
P
Boon
Tom
T
Van De Beek
Cees
C
Andersson
Swen-Olof
SO
Morris
Tom
T
Carroll
Kevin
K
D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000009:adverse effects*; D000813:Anilides / Q000009:adverse effects*; D001940:Breast / Q000528:radiation effects; D001941:Breast Diseases / Q000139:chemically induced / Q000532:radiotherapy; D016001:Confidence Intervals; D004311:Double-Blind Method; D004583:Electrons / Q000627:therapeutic use*; D006177:Gynecomastia / Q000139:chemically induced / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009570:Nitriles; D010146:Pain / Q000139:chemically induced / Q000532:radiotherapy; D011471:Prostatic Neoplasms / Q000628:therapy; D014105:Tosyl Compounds
D000726:Androgen Antagonists; D000813:Anilides; D009570:Nitriles; D014105:Tosyl Compounds; C053541:bicalutamide