In past posts, I have discussed the overtreatment of low grade prostate cancers and the risks such treatment creates for patients. There is great societal pressure to treat any cancer, even a low grade prostate cancer which is unlikely to do real harm. The treatments for prostate cancer are the same whether the grade is high or low. Regardless of the treatment chosen, there is a greater than 50% likelihood that the patient will be left impotent, incontinent or both. In addition to their physical effects on the patients, the treatments are quite expensive.
Years ago, doctors discovered that patients treated with the male pattern baldness drug finasteride had a lower incidence of prostate cancer. They also found that finasteride shrunk prostate cancer tumors. Despite these findings, the FDA has never approved finasteride as a treatment for prostate cancer. Finasteride is marketed under the names Proscar and Propecia.
There was a troubling aspect to this discovery: the patients who did develop prostate cancer had a higher proportion of aggressive, deadly tumors. The question then arose whether finasteride caused prostate cancer to become more aggressive. A recent study published in the New England Journal of Medicine provides reassuring information.
The authors of the study examined Social Security death records. They found that patients who took finasteride had essentially the same survival rate as those who did not. They concluded that this meant finasteride was not causing more aggressive tumors. If it were, those taking finasteride would die sooner than those who did not. What they believe finasteride does is to shrink the prostate and make it less likely that doctors will find and treat the low level prostate tumors. At the same time the smaller prostate makes it easier to find and treat the aggressive tumors. This explains why patients taking finasteride who are diagnosed with prostate cancer are more likely to be found to have aggressive tumors.
While I don’t think I will be asking for a prescription for finasteride any time soon, the findings are encouraging to the many doctors who believe that we overtreat low grade prostate cancers, often with disastrous consequences for the patient. They believe that any medication which will reduce the likelihood of treatment of low grade prostate cancers is good for patients and for the health care system as a whole, which can now channel its resources into treatments which are likely to actually make a positive difference in the life of a patient.
Here is a link to the article: http://www.nejm.org/doi/full/10.1056/NEJMoa1215932
