Doctors also found that some tumors shrank after men took the popular supplement, consisting of extracts from eight different herbs. The study, published Nov. 1 in the Journal of Clinical Oncology, is one of the first to subject the herb PC-SPES to rigorous scientific scrutiny. This is the first attempt to study this herb in a scientifically methodical way. Hormone-dependent prostate cancer is affected by the male sex hormone testosterone, which fuels prostate cancer growth.
Tumors shrink or slow their growth as testosterone levels are reduced.
As a result, PSA levels fall. Testosterone levels can be reduced by hormone medications, such as the female hormone estrogen, but tumors can become resistant to hormonal therapy. Hormone-independent prostate cancer continues to progress despite low testosterone levels. All of the men in the hormone-dependent group of the study had a PSA decline of greater than 80 percent, with a median period of that decline lasting 57 or more weeks. Only one patient had disease progression while taking the herbal supplement.