Long-Term Combined Androgen Blockade Alone for Localized Prostate Cancer.
The effect of long-term continuous combined androgen blockade (CAB) administered alone has been studied in 26 patients with stage B(2)/T(2) and 115 with stage C/T(3) prostate cancer who did not accept or were not candidates for other forms of therapy. In the 26 patients with stage T(2) disease who have received continuous CAB with an LHRH agonist and flutamide, progression of cancer, as evidenced by rising serum prostate specific antigen (PSA), was observed in only one patient receiving CAB, occurring after 7.3 years of continuous CAB treatment. Treatment with CAB was then stopped in 20 patients with stage T(2) cancer after a median period of 7.2 years. Failure or PSA rise occurred in 2 of these patients after a median follow-up of 3.1 years following cessation of CAB, and one died from prostate cancer. The benefits observed with CAB alone in localized disease compare favorably with those obtained by radical prostatectomy or radiotherapy alone. Twenty-six patients with stage T(3) cancer have been treated with CAB continuously for a median of 9.9 years. After a median follow-up of 4.4 years (range 0.3-7.0 years) after cessation of CAB in this group of patients, PSA failure was observed in 5 patients (19%), who had been treated continuously for 3.8, 5.0, 5.0, 9.9, and 10.9 years. Thus, in 85% (39 of 46) patients with stage T(2)-T(3) disease who were treated continuously with CAB for a median of 7.2 and 9.9 years, respectively, PSA remained undetectable up to a median of 3.1 (stage T(2)) and 4.4 (stage T(3)) years of follow-up. The present data, while showing the high efficacy of CAB in localized prostate cancer, clearly indicate the need for long-term treatment, similar to the 5 years of tamoxifen required for control of breast cancer.
Labrie
F
Prostate Cancer Clinical Research Unit, Department of Medicine and Laboratory of Oncology and Molecular Endocrinology, Laval University Medical Research Center, Centre Hospitalier Universitaire de Québec, Québec, Canada.
Cusan
L
Gomez
JL
Belanger
A
Candas
B