Strategy Might Thwart Resistance to a Common Prostate Cancer Treatment

It has been known for quite a while that high levels of testosterone lead to the growth of prostate cancer. However, there is a new study that challenges this conventional wisdom. A small recent study suggests that a treatment strategy known as bipolar androgen therapy can help in making prostate tumors more responsive to standard hormonal therapy.  In this therapy patients are made to alternate between low and high levels of testosterone.

The report of the study was published in the journal Science Translational Medicine recently.

Today, the primary treatment for advanced prostate cancer is hormonal therapy which typically aims to lower the levels of testosterone and prevent the tumor from growing. However, there is an issue with this treatment therapy. Prostate cancer cells eventually overcome the therapy by increasing their ability to suck up any remaining testosterone in the body. Through this new strategy, the tumor is forced to respond to higher testosterone levels again and thus it can aid in reversing its resistance to standard therapy.

Dr. Michael Schweizer, assistant professor of oncology at the University Of Washington School Of Medicine in Seattle and the study's lead researcher said that there are several larger trials that are going on and if confirmed it can lead to a new treatment approach for prostate cancers that have grown resistant to hormonal therapy. He also added that bipolar androgen therapy is still not ready for adoption into routine clinical practice as these studies have not been completed yet.

16 volunteers were chosen for the experiment. All of them had hormone therapy-resistant prostate cancer and they underwent bipolar androgen therapy.  These men didn’t have any symptoms from their cancer, like pain, and had been on standard hormonal therapy for an average of four years. Also, all of them had suffered impotence – a side effect of standard hormonal therapy for at least one year.

The results were encouraging – seven had their cancer go into remission, in four men the tumors shrank, and in one man, they disappeared completely. PSA (prostate specific antigen) levels are a standard signal of prostate cancer activity, as measured in a blood test. Schweizer said that about 50 percent of patients had declines in their PSA.

Dr. Samuel Denmeade, senior author of the study and co-director of the prostate cancer program at Johns Hopkins University in Baltimore said that he was of the opinion that the new approach has benefits beyond its effect on cancer cells. If a man’s testosterone levels are restored, many undesired side effects of effects of the hormone therapy like mood swings and not being able to have intercourse are also reduced.

Even though testosterone levels alternated between high and low, the participants seemed to tolerate the treatment well. Denmeade remarked that this treatment should not be thought of as a cure, but as a way to make men feel better and extend the time standard hormonal therapy remains effective. We hope that men taking this therapy will live longer, but we are not sure how long.  He also added that the bipolar androgen therapy might not be for “men who have not undergone any treatment for prostate cancer.

He also stressed that the long-term effects or dangers of the therapy are not known yet. Only longer studies and larger trials will help in finding out any risks associated with the treatment.

Dr. Anthony D’Amico, chief of radiation oncology at Brigham and Women’s Hospital in Boston is worried that alternating testosterone levels could actually shorten men’s lives. When a similar method was tried with estrogen in breast cancer, it caused early death.

References

https://medicalxpress.com/news/2015-01-strategy-thwart-resistance-common-prostate.html

https://health.usnews.com/health-news/articles/2015/01/07/strategy-might-thwart-resistance-to-a-common-prostate-cancer-treatment