Reducing Testosterone Levels by ADT in Men with Bony Metastatic Prostate Cancer Increases Survival Time
ByA study from Milan Italy looked at the most important question, does the lowering of testosterone levels through the use of androgen-deprivation therapy (ADT) increase survival time in men with metastatic prostate cancer? Since ADT comes with significant morbidity issues (the degradation of a man’s quality of life), can we expect to get an adequate benefit from ADT to balance out the negative side effects? This is the million dollar question for all of us when deciding to start ADT.
The researchers, Perachino M, Cavalli V, Bravi F., retrospectively reviewed the records of 129 men (a small study) with a histological diagnosis of metastatic bony-only prostate cancer and previously untreated with ADT. They then treated the men with 3 months of goserelin, a LHRH drug (ADT). Testosterone levels and prostate-specific antigen (PSA) levels were measured in the men every 3 months for the duration of the follow-up.
The following variables were factored into the final data analysis: the age of the men, diagnostic stage, Gleason score, basal PSA level, basal testosterone level, PSA nadir, time to PSA nadir, testosterone levels after 6 months, testosterone nadir and time to testosterone nadir. The data was analyzed using Cox’s proportional hazards models, with the primary endpoint being cancer-specific survival.
They found that the mean (standard deviation) basal PSA level was 185.8 (344.1) ng/mL, and the mean nadir PSA level 2.7 (8.6) ng/mL. The mean testosterone levels at baseline, 6 months and the nadir were 440 (200), 40 (40) and 21 (15) ng/dL. With a mean follow-up of 47.5 (29.7) months, 71 patients had died(55%) and 78 were alive (45%) at the time of analysis.
Statistical analysis using Cox’s model showed that in these men the risk of death was directly correlated not only to Gleason score (P < 0.01) and to the 6-month PSA level (P < 0.01), but also to the 6-month serum testosterone level they achieved (hazard ratio 1.32, P < 0.05).
The researchers concluded that there is a direct correlation between the risk of death and testosterone levels achieved during ADT. Their research supports the belief that lowering the testosterone level does provide life extension benefits.
Future studies need to expand the sample size of men as well as look into the potential mortality effects of ADT with men who have just a biochemical recurrence (PSA only) and with men who have soft tissue metastasis.
PubMed: PMID: 19747358
Joel T Nowak MA, MSW
