Objectives: To evaluate intermittent androgen suppression (IAS) in patients with prostate cancer and to try to define predictive factors for biochemical progression.
Patients and methods: From 1989 to 2001, 146 patients received IAS as a primary treatment for localized, advanced or metastatic prostate cancer (72 men) or as a treatment for prostate-specific antigen (PSA) recurrence after radical prostatectomy (RP) and/or radiation therapy (74 men). Androgen-deprivation treatment (ADT) was continued up to 6 months after PSA became undetectable or a nadir PSA level was reached. ADT was then re-instituted when the PSA level was> 4 ng/mL for patients who had RP or> 10 ng/mL for the others.
Results: After a mean (range) follow-up of 45.6 (12-196.9) months, 24 patients had biochemical progression. These patients were younger than those with no biochemical progression (67 vs 72 years, P = 0.004) and had a statistically higher Gleason score (7.21 vs 6.52, P = 0.01) and PSA level (111.1 vs 32.1 ng/mL, P = 0.05), and a shorter first phase without treatment (7.6 vs 11.2 months, P = 0.05). Overall 5-year metastatic disease free survival of 91.3%. The overall 5-year biochemical recurrence-free survival was 68%. Using multivariate analysis, a Gleason score of >or= 8 (P = 0.021), first-phase duration with no treatment of < 1 year (P = 0.044), positive lymph nodes or metastatic disease at the time of starting IAS (P = 0.023) and age < 70 years (P = 0.037) were the strongest predictors of biochemical progression.
Conclusion: IAS appeared to be a feasible treatment; the best candidates being those aged> 70 years with localized prostate cancer and a Gleason score of <or= 7.