Drs. Cote Skinner, et al. Published their study in 1998 in the British Journal of cancer on "The effect of finasteride on the prostate gland in men with elevated serum prostate- specific antigen levels."

They proposed that 5a-reductase activity might have some relationship on the incidence of prostate cancer, namely, in its possible prevention. We are all aware of its effects on prostate volume and the use in patients with benign prostate hypertrophy, but this study aimed to examine the effects of finasteride on theorized markers for "malignant potential," cellular proliferation, and high grade prostatic intraepithelial neoplasia (PIN). High-grade PIN lesions are considered premalignant lesions. If there were some chemopreventative effect, they expected to see a decrease in cellular proliferation and fewer patients with PIN lesions or less severe lesions.

The subjects included in the study were men 50 years and older with elevated PSA levels (>4ng/ml). Pre-study ultrasound-guided biopsies were obtained to exclude patients with pre-existing cancer. Eventually 58 men were enrolled in the study and were randomized to a treatment and control group, stratified based on age and PSA levels. The treatment group received finasteride 5mg/day. The length of the study was one year, with pre-study and interval evaluation of PSA, dihydrotestosterone (DHT), and testosterone (T) serum levels. Prostate biopsies were obtained at the endof the study looking for cellular proliferation/hyperplasia, high grade PIN lesions, and prostate cancer.

The results for serum levels of PSA, DHT, and T were as expected, a decrease in both PSA and DHT and an increase in T. The biopsy results were somewhat of a surprise. The theorized markers of potential malignancy, cellular proliferation, and hyperplasia, showed no difference between the treatment and the control group.
The rate of PIN lesion detection was no different between groups either.
The case for chemoprevention seemed to be much less convincing.

The results of the biopsies looking for prostate carcinoma is the one that should make us do a double take. Of five patients in the control group (no finasteride) with high-grade PIN lesions in the pre-study
biopsy, none showed evidence of cancer in the post-study biopsy. In the finasteride treated group, where eight patients had PIN lesions on the pre-study biopsy, 6 (75%) had post study biopsies with cancer. This difference was statistically significant with P=0.021.

Final comment: What will you say the next time a 45-50 year old male presents with a Norwood class III or greater pattern, is interested in finasteride, has no documentation of his serum PSA level, and asks if finasteride is safe?

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