Based on my limited understanding of how HT works, I think the time you need to be on HT depends on the doubling time of the cancerous cells.
The idea, again in my assuredly non-medical perspective, is that PCa cells need testosterone primarily when they divide, when they duplicate. So, the idea is by stopping T, they die when they try to divide. Prostate cells are some very slowly dividing cells by their nature, something like 2.5 years or so. Cancerous cells would divide faster (the doubling rate). So any cell about
to divide would be affected first, and cells that just did it would linger 2.5 years before doubling again. So the idea of a 3 year sentence was to hurt all of the prostate cells that try to divide, all the way out to the maximum.
Since cancer cells would divide faster, probably much faster, maybe shorter terms on HT hurt them enough to stop the process if it happens sooner. If we want to whack cells reproducing in 6 months, 12 months, or some such, then as long as the HT is in place longer, then maybe that's all that's needed.
Radiation also hurts their ability to divide, messing up the DNA so they just die when they attempt it. Combined with lack of T, apparently it's a double-whammy.
Maybe it is used for other functions too, so maybe they depend on testosterone more than that. I don't know. Just another perspective, trying to look at the underlying physics of the problem.
55@Dx on 4/16/13. PSA 5.2, G9(5+4), PNI+, cT3a by MRI.
IGRT - 44 sessions (79.2 Gy, 50.4 Gy pelvic)
ADT2 - Lupron+Casodex (5/13-3/16)
8/13-5/16 <0.1 (ADT2)
5/16-3/17 recovering from ADT2
3/17-7/18 ~ 0.6 - 0.8 (no TX)
10/18 = 1.0My Story