Finasteride, is a 5-alpha reductase inhibitor that prevents the conversion of testosterone to dihydrotestosterone (DHT). In the 5-mg dose, it has been used for the treatment of non-cancerous prostate tumors and in the 1-mg dose has been prescribed both as a prevention and treatment for early onset male pattern baldness. However, some caution was taken when a study conducted in 2003 by the National Cancer Institute suggested that while Finasteride 5mg (Proscar) might be responsible for a 25% reduction in the overall incidence of prostate cancer, it might also be responsible for an increase of 25.5% in high-grade, aggressive tumors detected in these patients when compared to the placebo group. This random study was conducted on a group of 18,000 men.
The 2003 study, however, did not conclude whether the increased incidence of high-grade tumors was caused by finasteride or if finasteride, in fact, aided in the detection of pre-existing high grade aggressive cells.


