So how long does it usually take for men undergoing hormone therapy (ADT) to progress from being hormone dependent to hormone independent? Clearly, we should always remember that this is a very individual, case-by-case time. However, there was a recent time analysis published in the February 2009 edition of Urology.
These researchers found that after an average of 18-24 months under ADT, almost all patients with advanced or recurrent prostate cancer show uncontrolled PSA progression despite their therapy. They also found that at this hormone-independent stage, a PSA regression can be achieved by secondary hormonal manipulation in approximately 50% of men for an additional 6-12 months before they become truly hormone-refractory.
They also pointed out that after PSA progression under complete androgen ablation, in 40% of cases a temporary additional regression can be achieved by discontinuing of the anti-androgen drugs. The administration of an alternative anti-androgen results in a PSA decrease in 80% of the patients responding to anti-androgen deprivation. Inhibition of the adrenal testosterone synthesis by oral administration of ketoconazol (secondary hormone blockade) can further delay disease progression.
Transdermal application of estrogen also allows temporary control of tumor activity by modulating the LHRH and testosterone release as well as directly effecting tumor cell apoptosis. Recent therapeutic modalities as for example somatostatin analogues influence the micro environment of tumor cells and thereby intensify the effect of anti-tumor therapy.
Original article written by:
Schilling D, Gakis G, Bökeler U, Stenzl A, Kuczyk MA, Merseburger AS.
Urology A. 2009 Feb;48(2):183-90.
Remember, everyone will progress at different rates, some of us faster than others will.
Joel T Nowak MA, MSW
I have not seen this study prior to your sending the link, but I am familiar with MDX-010. In the states there is actually 6 different clinical trials currently going on (see http://www.clinicaltrials.gov and search MDX-010 prostate cancer).
The specific study you sent only showed, and in a small number of subjects, that the tumors dramatically shrank. Hopeful this is good, but at this time there is no evidence that it actually extends survival, the gold standard for FDA approval in the U.S.
This particular study is very preliminary and seems very hopeful. Only time will tell and unfortunately as we have learned the process for demonstrating success and then finally achieving drug approval is many, many years away.