From the article:
Previous studies, he adds, have shown that taking testosterone at the wrong time – particularly by men with symptoms of active cancer progression who have not yet received testosterone-blocking therapy – can make the disease worse.
In men whose prostate cancer spreads, doctors typically prescribe drugs that block testosterone production, but cancer cells eventually become resistant to this means of reducing the hormone, says Denmeade, a professor of oncology at the Johns Hopkins University School of Medicine. At that point, physicians switch to other drugs, such as enzalutamide, which block testosterone’s ability to bind to receptors within prostate cancer cells.
Denmeade says the combination of drugs that block testosterone production and receptors, called androgen deprivation therapy, may make prostate cancer more aggressive over time by enabling prostate cancer cells to subvert attempts to block testosterone receptors. And many men on these drugs experience harsh side effects, including impotence, weight gain, muscle loss and intense fatigue.
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With this context, the new study tested an approach based on the idea that if prostate cancer cells were flooded with testosterone, the cells might be killed by the hormone shock. The cells also might react by making fewer receptors, which may make the prostate tumor cells vulnerable once more to androgen deprivation therapy.
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The men were given three 28-day cycles of an intramuscular injection of testosterone and two weeks of a chemotherapy drug called etoposide. Men who showed decreases in PSA levels after three cycles were continued on testosterone injections alone.
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Of the 14 remaining in the trial, seven experienced a dip in their PSA levels of between 30 and 99 percent, an indication their cancers were stable or lessening in severity. Seven of the men showed no decrease in PSA.
In addition, four of the seven men stayed on testosterone therapy for 12 to 24 months with continued low PSA levels. Of 10 men whose metastatic cancers could be measured with imaging scans, five experienced tumor shrinkage by more than half, including one man whose cancer completely disappeared.