Combining short-term androgen deprivation with radiation provides better outcome

A new study presented at the American Society of Clinical Oncology annual meeting in Chicago suggest that short-term androgen deprivation therapy (STADT) in combination with radiotherapy (RT) in men with intermediate-risk prostate cancer is associated with better outcomes compared with dose-escalated radiotherapy alone.

Androgen deprivation therapy may be used for a number of reasons such as if the cancer has spread too far to be cured by surgery or radiation or if the cancer remains or comes back (aka the patient has experienced a recurrence) after treatment with surgery or radiation therapy. It may also be used in combination with radiation therapy as an initial form of treatment if the patient is at higher risk of the cancer coming back after treatment. The chance of a prostate cancer recurrence is based on a high Gleason score, high PSA level, and/or if the prostate cancer tumor has grown beyond the prostate gland. Lastly, androgen deprivation therapy may also be used prior to radiation in an attempt to reduce the size of the prostate cancer tumor, which if successful, would make for a more effective treatment.

Radiation therapy uses beams or high-energy rays to kill prostate cancer cells. It is most often referred to as external beam radiation therapy. Radiation therapy may be used as the primary treatment for low-grade prostate cancer that is still confined to the prostate gland, as the primary treatment in combination with androgen deprivation therapy for prostate cancer that has grown beyond the prostate gland and into nearby lymph nodes or organs. Radiation therapy may also be used if the cancer has not been completely removed or recurs within or near the prostate after surgery. And lastly, it may also be used if the cancer is advanced in order to reduce the size of the tumor and to provide relief from present and possible future symptoms.

The study was conducted by Dr. Abdenour Nabid, MD, of Centre Hospitalier Universitaire de Sherbrooke in Sherbrooke, Quebec, Canada, as well as his colleagues. The researchers recruited 600 men with intermediate-risk prostate cancer who were randomly given six months of short-term androgen deprivation therapy and two levels of prostate radiotherapy doses or prostate dose-escalated radiotherapy alone. The study participants were all an average age of 71 years old, had a median PSA level of 10.0 ng/mL, and median Gleason score of 7. The researchers stated that these characteristics among the patients provided a decent balance for their investigation. 

The researchers followed up on the patients after about 6.5 years. They found that among the 600 patients, biochemical failure occurred in 96 patients (16 percent). According to Renal and Urology News, “The failure rates were 13.5 percent, 11 percent, and 23.5 percent in arms 1, 2, and 3, respectively. The differences between arms 1 and 3 and arms 2 and 3 were statistically significant, but the differences between arms 1 and 2 were not, according to the investigators. The 5- and 10-year disease-free survival (DFS) rates for arms 1, 2, and 3 were 92.8 percent, 97.1 percent, and 85.5 percent, respectively, and 78.4 percent, 78.3 percent, and 65.9 percent, respectively. The differences in 5- and 10-year DFS rates between arms 1 and 3 and arms 2 and 3 were statistically significant, but the differences between arms 1 and 2 were not. The researchers found no significant differences among the 3 arms with respect to overall survival.”

Androgen deprivation therapy is also known as androgen suppression therapy or more commonly as hormone therapy. Androgen deprivation therapy works for prostate cancer patients by decreasing or inhibiting the levels of male hormones (androgens) in the body in order to stop the prostate cancer cells from growing.