By Charlie Schmidt
Prostate cancer cells need testosterone to grow and flourish. Interfering with the body’s ability to make and use this hormone, also known as an androgen, has been a mainstay of treating advanced prostate cancer since the 1970s. This approach is called androgen-deprivation therapy (ADT) because it cuts off the supply of testosterone to prostate cancer cells and the rest of the body.
In men with cancer that has spread beyond the prostate gland, radiation therapy plus ADT can ease symptoms and improve survival. But some doctors give ADT by itself to millions of men with localized tumors that haven’t spread beyond the prostate. Some experts see this as an alarming trend because ADT’s side effects can include impotence, bone fractures, weight gain, diabetes, and heart disease. Guidelines for treating prostate cancer have never supported the use of ADT for early-stage (localized) prostate cancer.
A new study out of Rutgers University shows that men with localized prostate cancer don’t live longer if they’re treated with ADT. Lead author Grace L. Lu-Yao, a researcher at Rutgers Cancer Institute of New Jersey, told me that for these men, “ADT will not be beneficial” with respect to survival benefits. The study was published online in JAMA Internal Medicine.
Lu-Yao and her colleagues studied more than 66,000 men aged 66 years or older who were diagnosed with localized prostate cancer between 1992 and 2009. The researchers followed the men’s health and survival using records maintained by the National Cancer Institute and the Center for Medicare and Medicaid Services. Men who got ADT did not live any longer than men who did not get hormone therapy.
At 110 months, the new study’s average follow-up time was significantly longer than previous investigations that reached the same conclusion. For instance, after reviewing records from 15,170 men diagnosed with localized prostate cancer between 1995 and 2008, investigators from Georgetown University Medical Center in Washington, DC, saw no survival advantage among men treated with ADT. Writing in the Journal of Clinical Oncology, the researchers did suggest that men with more aggressive tumors might benefit from the treatment, though that remains to be proven.
Why might a doctor prescribe ADT for a man with localized prostate cancer even though there’s little evidence to support this approach? ADT might look like a proactive step for a man who wants to pursue all available options. And even though survival may not be affected, doctors may have other reasons for considering ADT, especially for older men who may be too ill to undergo surgery to remove the prostate, or who may have other reasons for not undergoing radiation therapy.
“In these instances, ADT can help with urinary difficulties or to shrink the prostate before other therapies,” says prostate cancer specialist Dr. Marc B. Garnick, the Gorman Brothers Professor of Medicine at Harvard Medical School and Beth Israel Deaconess Medical Center, and Editor in Chief of Harvard Medical School’s 2014 Annual Report on Prostate Diseases.