Annihilating Recurrent Prostate Cancer and Decreasing Side Effects
Most men who are diagnosed with prostate cancer face one of just a few options for their treatment plan: watchful waiting—having their physician monitor the level of their prostate-specific antigen, or PSA, to ensure it doesn’t rise incrementally—or curative therapy, usually surgery.
Despite the name, curative therapy doesn’t always lead to a cure. After surgery, the patient’s blood is tested for the presence of PSA. If PSA is detected in significant amounts, more testing and action must be taken. But until recently, there hasn’t been a clear path for continued treatment to eradicate the remaining cancer cells.
Some patients will begin watchful waiting after a failed curative therapy. For men whose PSA levels are very low and stable, this is often the best choice. Others are put on continuous hormone therapy to try to control their cancer.
But for many patients, especially those with rising PSA levels, the next therapy of choice is radiation therapy.
While radiation can be effective, it is also highly toxic and leads to a number of potential side effects over time, particular after 10 years following radiation treatment. These include continued loss of urinary continence, frequent diarrhea and/or constipation, and the potential loss of sexual potency (the ability to get or maintain an erection).
Rapidly and consistently rising PSA levels also may indicate metastatic cancer. In other words, a man could go through rounds of radiation therapy, suffering unpleasant and significant side effects along the way, only to still have his prostate cancer spread.
I am currently leading research at Roswell Park of a new way to deliver androgen deprivation therapy, or ADT, to men whose surgeries did not eradicate the cancer, and for whom radiation would not likely help them toward cure. These men account for roughly one-third of all men who undergo prostatectomy (surgical removal of the prostate).
Androgen is a hormone that fuels the growth of prostate cancer. ADT uses drugs to block these hormones in order to stop prostate cancer cells from multiplying. With traditional ADT, four agents, or drugs, are given in sequence.
Our new study would have the four drugs, plus one additional drug, administered to these patients right after curative surgical therapy fails. We would skip entirely over radiation therapy.
We believe that by administering these drugs at one time in an almost “mega-dose” versus in succession, this therapy could annihilate most of the remaining cancer cells, and the patient’s immune system would be able to destroy the remaining few cancer cells.
Because four of the five drugs are already used safely to administer ADT, we believe this new method will also be safe and offer minimal side effects.
If the results of our current laboratory study are promising, as we expect they will be, the next step would be to bring this new option to patients through a clinical trial. Our hope and belief is that this new approach to offering therapy to men most at risk of prostate cancer recurrence after surgery will soon be a less toxic, more effective treatment option for prostate cancer patients who remain in need of a cure.