It is my understanding that in the early days chemotherapy wasn't very effective for prostate cancer probably because chemo acts best on fast-growing cells and prostate cancer grows slowly. Through the years it has been used at later periods after a patient's cancer no longer responds to hormones. However, there seems to be a renewed interest in using chemo earlier in the process for high-risk patients likely to recur. There are currently several clinical trials going on to test this, I believe. The rationale is that the chemo chemicals used today are much more effective, using it earlier in the process means the men are much healthier than men late in the process so more able to tolerate higher chemo levels, and the now established success of early chemo in cancers such as breast cancer. Adding a form of Vitamin D seems to work well and increase the effects (but with some toxicities) of the chemical used most commonly today. There is now a new form of Vitamin D in studies which they are saying is more effective and much less toxic.