Longitudinal analysis of sexual function reported by men in the Prostate Cancer Prevention Trial.
ABSTRACT The Prostate Cancer Prevention Trial (PCPT) was a randomized, double-blind, placebo-controlled study of the efficacy of finasteride in preventing prostate cancer in 18,882 men aged 55 years or older. The PCPT offered an opportunity to prospectively study the effects of finasteride and other covariates on sexual dysfunction.
We assessed sexual dysfunction in 17,313 PCPT participants during a 7-year period. A battery of questionnaires assessed sexual dysfunction (Sexual Activity Scale score); age; race; SF-36 Mental Health Inventory-5, Physical Function, and Vitality scores; body mass index; smoking status; and the presence of diabetes and hypertension. Assessments began at month 6 after random assignment and included the Sexual Activity Scale score at randomization as a covariate. Two-sided general t tests, with a cutoff of P value less than .05, were used to determine the statistical significance for mixed model effects with correlated random time slopes and intercepts. The changing impact of covariates on sexual dysfunction was also assessed at 6 months, 3.5 years, and 6.5 years after randomization.
Finasteride increased sexual dysfunction only slightly and its impact diminished over time; the increase in the Sexual Activity Scale score relative to placebo of 3.21 points (95% confidence interval [CI] = 2.83 to 3.59 points; P<.001) at the first assessment decreased to 2.11 points (95% CI = 1.44 to 2.81 points; P<.001) at the end of study. These Sexual Activity score values were small on a scale of 0-100, the range observed in the study, and in comparison with individual variation. After adjustment for all covariates, mean sexual dysfunction increased in both arms from baseline (6 months after randomization) by 1.26 Sexual Activity points (95% CI = 1.16 to 1.36 points; P<.001) per year, corresponding to a cumulative increase of 8.22 points (95% CI = 7.52 to 8.92 points; P<.001) over the study period.
The effect of finasteride on sexual functioning is minimal for most men and should not impact the decision to prescribe or take finasteride.
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ABSTRACT: Because prostate cancer has a long latency and high incidence, it is a good target for chemoprevention by agents such as retinoids, antiandrogens, antiestrogens, and vitamin D analogs. Phase II chemoprevention trials are frequently conducted on cohorts of patients with previous cancers or premalignant lesions who are scheduled for prostate cancer surgery; such trials are currently in progress with several agents. Prostatic intraepithelial neoplasia (PIN) can be used as a surrogate endpoint biomarker for prostate cancer incidence. Studies of men with high-grade PIN (HGPIN) are particularly useful in that they require a much smaller cohort of 200-400 patients instead of the 18 000 patients required for typical Phase III trials. Even with a smaller sample size, statistically significant evidence of cancer prevention is achieved due to the high probability of HGPIN progressing to cancer (35-55%). A Bayesian sequential monitoring system allows interim analysis of biomarker modulation as early as the completion of 30 patients. Putting all these strategies together will help inhibit, delay, or modulate the natural history of prostate carcinogenesis.Prostate cancer and prostatic diseases 02/1999; 2(S1):27-33. DOI:10.1038/sj.pcan.4500274 · 2.83 Impact Factor