A new study suggests that combining a breast cancer drug with hormone therapy could be a more effective strategy to reduce the progression and recurrence of prostate cancer in men.
This year, around 26,730 men are expected to die from prostate cancer, making it the third leading cause of cancer death for men in the U.S.
Hormone therapy, or androgen deprivation therapy (ADT), is a common treatment for prostate cancer, particularly for men with advanced forms of the disease.
ADT works by reducing levels of male hormones called androgens - including testosterone and dihydrotestosterone - that fuel the growth of prostate cancer cells.
While the treatment can be effective, it does not work for all patients with prostate cancer; some men may experience a recurrence of the disease.
The research was led by Dr. Mohammad Asim, from the University of Surrey in the United Kingdom.
PARP inhibitors and ADT: A winning combo?
To reach their findings, the team used a variety of analytic techniques to assess how prostate cancer cells respond to ADT.
They found that while ADT is effective for killing prostate cancer cells, the therapy also prompts the activation of poly ADP ribose polymerase (PARP) enzymes in these cells. PARP enzymes trigger DNA repair, which encourages cancer cell growth and helps them to evade hormone therapy.
The researchers then sought to determine whether PARP inhibitors - which are a class of drugs already used for the treatment of breast cancer - might help to boost ADT efficacy.
On treating prostate cancer cell lines with both ADT and PARP inhibitors, the researchers found that the latter effectively prevented the DNA repair process in prostate cancer cells, therefore causing them to die.
These results, say the researchers, suggest that PARP inhibitors could be added to ADT as a means of improving survival for men with prostate cancer.
"Our research shows that anti-hormone treatment could be combined with PARP inhibitor[s] to prevent the progression of the disease."
Dr. Mohammad Asim
Dr. Catherine Pickworth, of Cancer Research UK, says that the study "adds to the growing evidence that some men with prostate cancer could benefit from being given PARP inhibitors alongside hormone deprivation treatment."
"The next step is to carry out clinical trials to test if this treatment combination is safe to use in patients and if it helps more men survive the disease," she adds.