What Is Dutasteride?
Dutasteride (marketed under the trade name Avodart) has been used extensively in the past to treat men with benign prostatic hyperplasia (BPH). It is a member of the class of drugs known as 5 alpha-reductase inhibitors. These drugs work to lower the amount of DHT (a hormone similar to testosterone) and allow men with enlarged prostates to urinate more freely.
What Does It Have to Do With Prostate Cancer?
Prostate cancer is known to grow in response to male hormones such as testosterone or DHT. Because dutasteride (and other drugs in this class) work by lowering the amount of DHT, it was long thought that it may have potential for lowering the risk of developing prostate cancer.
What Do We Know About Its Effect on Prostate Cancer Risk
A large trial completed in 2003 looked at the effect of giving finasteride (a drug in the same class as dutasteride) to men at risk for prostate cancer. That study showed a roughly 25% reduction in the rate of prostate cancer in men receiving the medication versus those receiving a placebo. The results of this study were questioned by many top researchers, however, because of flaws in its design and a number of questions that went unanswered.
This initial study, the Prostate Cancer Prevention Trial, was published in the New England Journal of Medicine.
Another large trial released in 2010 in the New England Journal of Medicine that looked at the use of dutasteride to reduce prostate cancer. This study followed roughly 6,700 men who had high PSA levels, but no diagnosed prostate cancer. Half of these men were given dutasteride and the other half were given placebo.
At the end of a four-year monitoring period, the groups of men were compared. Those who had been given dutasteride were found to have up to a 23% lower risk of developing certain types of prostate cancer.
Unfortunately, the results again were not completely clear-cut about the benefits of the medication. In this study, men who were given dutasteride were found to have significantly higher rates of high grade (high Gleason score) cancer, although it is possible that this is just an artifact of the way the study was designed. They were also found to have more heart problems and to have reported more sexual dysfunction than the men who were given a placebo.
So, Should High-Risk Men Take Dutasteride to Lower Their Prostate Cancer Risks?
Unfortunately because significant risks were shown to be associated with taking dutasteride in this most recent study, there is no clear-cut answer as to whether men who are at high risk for prostate cancer should take dutasteride to lower their prostate cancer risk.
For men at high risk of prostate cancer, discussing this option with your doctor is the best course of action until more conclusive data come to light.
Sources:
Andriole GL, et al. Effect of dutasteride on the risk of prostate cancer. N Engl J Med. 2010 Apr 1;362(13):1192-202. Thompson IM, et al. The Influence of Finasteride on the Development of Prostate Cancer. N Engl J Med. 2003 Jun:349:215.
