Primary androgen deprivation ineffective for most early prostate cancer
In a study of more than 15,000 men with early stage prostate cancer, 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 Lombardi Comprehensive Cancer Center in Washington, DC, said that the risks of serious adverse events associated with the treatment, which has been linked to impaired cognition, heart disease, diabetes and other disorders, "mitigates 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 (2014; doi:10.1200/JCO.2013.52.5782), drew 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 (localized) and did not have surgery or radiation therapy, considered curative treatment.
Androgen deprivation therapy suppresses the production of testosterone, the male hormone said to fuel 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 who have metastatic prostate cancer. 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," said the study's lead investigator, Arnold Potosky, PhD, of Georgetown Lombardi. "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."
Use of primary androgen deprivation therapy 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 men age 65 years and older. The study did not compare androgen deprivation therapy directly to surgery or radiation therapy, the two main curative treatment options for prostate cancer.
While the study did not probe the reasons why physicians prescribe the treatment in this setting, it was much more common in older men and those with higher risk of disease progression. Potosky speculated that men and their doctors may feel the treatment is a useful option to delay progression of prostate cancer for those who are not good candidates for, or who prefer to avoid, surgery or radiation due to 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."