Medical androgen deprivation therapies combined with other treatments may cause relapse in patients with prostate cancer.
In a study published by Science Translational Medicine, researchers found that androgen deprivation therapies (ADTs) may suppress adaptive immune responses.
This suppression prevents immunotherapies from working properly, the study noted.
"Medical ADTs have been used for a half century to treat prostate cancer, and promising clinical results for cancer immunotherapy have led to attempts to combine it and other standard-of-care therapies with immunotherapy to treat the disease," said senior author Yang-Xin Fu, MD, PhD, in a press release.
Researchers found that some ADTs can reduce T cell response against prostate cancer, which can lead to tumor relapse. Suppressed immune systems block the efficacy of any immunotherapy and can lead to relapse.
Some patients could have a poor immune response due to the radiation or chemotherapy suppressing the immune response, the study noted.
Researchers said that although these treatments may suppress the immune response, resistant clones will survive and the tumor can relapse more aggressively.
Regulating timing, types, and dosage of ADTs used with immunotherapy can greatly maximize the treatment, the study concluded.
"We hope that our findings will cause physicians to think twice before starting chemotherapy or radiation on their cancer patients, to consider the best way to combine them with immunotherapies," Dr Fu said. "The idea is to kill the tumor cells while also considering whether these therapies are suppressing or activating the immune system."