Examining the benefits of combining hormone therapy and radiation therapy

This study examined the evidence for combining androgen deprivation therapy (ADT) with radiation therapy for the treatment of high-risk localized prostate cancer. Authors concluded that the combined therapy approach was associated with a survival advantage for intermediate- and high-risk patients. 

ADT is a type of hormone therapy used to treat prostate cancer. It targets the production of male hormones (such as testosterone) and reduces their effect on cancer cell growth. ADT is often the first-line treatment for advanced prostate cancer, including cancer that has spread. It is less commonly used on its own for localized (confined) prostate cancer. However, ADT can be combined with other treatments, such as radiation therapy (RT), for a more intensive treatment of localized prostate cancer. This is often recommended when the risk of disease recurrence after treatment is high. 

The aim of this study was to summarize evidence on the combined use of ADT and RT for high-risk localized prostate cancer.  

One study reported a benefit of long-term ADT (3 years) after RT in men with locally advanced disease (tumor protruding into nearby tissue). The 10-year overall survival rate (proportion who have not died from any cause since treatment) was 39.8% for men treated with RT alone. In contrast, the 10-year overall survival rate was 58.1% with additional long-term ADT. Two separate studies noted a survival benefit of ADT plus RT over ADT alone. Combining ADT with RT was also found to be beneficial for high-risk patients after other treatments have failed.

Men with high-risk disease treated with RT benefited more from long-term ADT (3 years) compared to short-term ADT (6 months). One study noted a long-term (average follow-up 11.3 years) overall survival rate of 45.1% for long-term ADT. This was significantly higher than for short-term ADT (31.9%).

ADT administered before RT can reduce prostate size by about 25 to 30%. 10-year overall survival rates have been found to favor ADT administered before RT (43%) compared to RT alone (34%). However, this was not significant for men with high-risk prostate cancer. A number of studies have suggested that the optimal duration of ADT administered before RT is between 4 to 6 months for men with intermediate-risk prostate cancer. 

Authors concluded that ADT administered before, during, or after RT offers a survival benefit for high-risk localized prostate cancer patients. Men at intermediate risk or with locally advanced disease may also consider a combined therapy approach.