Finasteride ( Proscar ) blocks an enzyme called 5-alpha-reductase, which is necessary to change testosterone to another hormone that causes the prostate to grow.
It is used to treat urinary problems caused by enlargement of the prostate ( benign prostatic hyperplasia or BPH ).

The results from the Prostate Cancer Prevention Trial ( PCPT ) showed that prostate cancer could be prevented through chemoprevention.
The study found that Finasteride reduces the incidence of prostate cancer by 24.8 percent compared to a placebo.
However, a possible increase in the number of high-grade tumors in the trial prompted many to question whether any benefits of the drug would be offset by an increase in mortality related to the higher-grade tumors.

No difference in mortality was seen during the 7 years of PCPT.
An analysis by researchers at the Fred Hutchinson Cancer Research Center in Seattle suggests that the potential detrimental effect of an increased rate of patients with prostate cancer with high-grade Gleason scores would be outweighed by reduced incidence.

Assuming a 24.8 percent reduction in the incidence of prostate cancer for five years among U.S. males aged 55 years or older, the authors estimated that 316,760 person-years would be saved because of Finasteride.

An absolute increase of 6.9% in the proportion of United States men with high-grade tumors ( corresponding to the difference between the rates of the placebo and Finasteride groups of the PCPT ) would reduce the number of person-years saved ( PYS ) to 262,567.

For each absolute increase of 5% in the proportion of patients with high-grade tumors based on Gleason scores, the number of PYS would be reduced by approximately 39,000.

Source: Cancer, 2005


XagenaMedicine2005