Primary Androgen Deprivation Therapy Ineffective for Most Men With Early Prostate Cancer
Study finds same survival in treated and untreated patients
A study of more than 15,000 men with early-stage prostate cancer has found that those who received androgen deprivation as their primary treatment instead of surgery or radiation did not live any longer than those who received no treatment.
The research team, led by scientists at Georgetown University’s Lombardi Comprehensive Cancer Center, say that the risks of serious adverse events associated with the treatment — which has been linked to impaired cognition, heart disease, diabetes, and other disorders — “mitigate against any clinical or policy rationale for use of primary androgen deprivation therapy in these men.”
The findings, reported in the Journal of Clinical Oncology, draw from cancer registries linked with extensive electronic medical records in three large, integrated health plans. The men included in the study had prostate cancer that had not spread beyond the organ (i.e., localized disease) and had not received surgery or radiation therapy, considered curative treatment.
Androgen deprivation therapy suppresses the production of testosterone, the male hormone believed to fuel the growth of prostate cancer. The therapy improves survival when given with radiation for later stages of disease and is considered the standard of care for men with metastatic prostate cancer. The effectiveness of primary androgen deprivation therapy (PADT) has not been established.
“This study is the most comprehensive study on the effectiveness of PADT for men who forgo radiation and surgery for their localized prostate cancer, and it tells us there is no strong reason to use it in most patients,” says lead investigator Arnold Potosky, PhD. “We found only a small survival benefit for primary androgen deprivation therapy compared to no therapy in men diagnosed with higher-risk localized prostate cancer."
The use of PADT for early-stage prostate cancer is widespread. Despite the lack of randomized clinical trials to test its effectiveness, recent studies have reported it as the second most common treatment, after radiotherapy, for clinically localized prostate cancer among older men (aged 65 years and older). The study did not compare androgen deprivation therapy with either surgery or radiation therapy, the two main curative treatment options for prostate cancer.
While the study did not probe the reasons why physicians prescribe androgen deprivation in this setting, it was much more common in older men and in those with a higher risk of disease progression. Potosky speculates that men and their doctors may feel that the treatment is a useful option to delay the progression of prostate cancer in men who are not good candidates for, or who prefer to avoid, surgery or radiation because of their side effects.
“Primary androgen deprivation therapy may be preferable to some men with early-stage prostate cancer who would prefer to do something rather than watch and wait for further signs of progression to occur later and then need treatments,” Potosky adds. “However, using PADT by itself immediately after diagnosis in the hopes of limiting cancer’s progression does not extend survival, according to this study.”
The researchers are now using their database of 15,170 patients to examine the rates of potential side effects from the treatment.
“Given the aging American population, more men are likely to be faced with prostate cancer, so it is very important to understand whether the risks of primary androgen deprivation therapy outweigh the survival benefit,” Potosky says. “Ultimately, this is a decision for men and their doctors to make together, and we hope that our study provides some helpful information to guide these decisions.”
Source: EurekAlert; March 17, 2014.