I don't really like the phrase "feed on testosterone". Testosterone does not provide the cell with any nutrient, it just acts as a trigger.
I don't know much about cell biology and hormones, but I'll give you my take on it anyway. Men and women are pretty much identical. Men do have a Y chromosome but it doesn't do much, for example all the details of making sex organs male or female are on various other chomosones. All the Y chromosone does is trigger testosterone in the fetus, that then tells some of the cells to start becoming male cells, like penis, testicle, prostate etc.The testicles then carry on making testosterone for life.
By stopping testosterone in an adult man some of those male cells suddenly think "what am I doing here? I'm in a woman! " hence they become dormant. If you then replace the testosterone they are triggered to carry on as normal.
So testosterone is just a signal not food. Pretty much like music and dancing is to me, give me music and I will dance, no music: no dancing. Music is just the signal. But dancing or not I need food.
Sadly prostate cancer cells eventually evolve to divide even without testosterone.
The fact you are asking this question, suggests you are hoping to find the secret which will cure cancer. Well join the people in white coats they are all looking, but it is taking time.
I don't know how much money you have, if you are in the Bezos, Musk, Branson league you may make some progress. Mind you Steve Jobs wasn't short of a bob or two (sorry english idiom) and he went down the wrong route.
Even if you do have enough money to set up your own research project, it is unlikely to yield fruit until after you die of cancer. So take what is on offer now to delay your death until a cure is found.