SAN FRANCISCO—Adding radiotherapy to oral anti-androgen therapy dramatically reduces long-term prostate cancer–specific mortality rates among men with locally advanced prostate cancer, according to researchers reporting updated clinical trial data at the 2014 Genitourinary Cancers Symposium.
The Scandinavian Prostate Cancer Group Study VII began in 1996, when standard treatment was hormone therapy alone, noted lead study author Sophie Fosså, MD, PhD, of Oslo University Hospital in Oslo, Norway.
But “this trial continues to show that adding radiotherapy substantially boosts long-term survival,” Dr. Fosså said. “This combination more than doubles the 10-year survival rate and confirms that this approach should be a standard option for men with this type of prostate cancer who are expected to live at least another 10 years,” she said.
The updated analysis represented 11 years of observation, and an analysis of mortality data from Norway’s and Sweden’s national death registries. For men receiving hormone therapy only, prostate cancer–specific mortality rates were 18.9% at 10 years and 30.7% at 15 years compared with 8.3% and 12.4% among men receiving radiotherapy as well; (overall survival at 15 years was 56.7% versus 43.4% (hazard ratio [HR], 0.70; P = 0.0006).
A total of 875 men in Norway, Sweden, and Denmark participated in the study. All were younger than 75 years of age, with locally advanced or high-risk prostate cancer, prostate-specific antigen 70 μg/L or lower, and “good general health,” Dr. Fosså said. Patients underwent medical castration, and were randomly assigned 1:1 to receive continued anti-androgen therapy alone, or with 70 to 74 Gy conformal three-dimensional radiotherapy.
“In these patients, the combination of radiotherapy and hormones may be considered a standard curative treatment option,” she concluded.
The addition of radiotherapy to hormone therapy was associated with impaired sexual function and bowel problems—issues that should be discussed with patients prior to treatment, Dr. Fosså noted.
“It’s interesting to see these results improved over time,” commented panel moderator Charles J. Ryan, MD, of the Helen Diller Family Comprehensive Cancer Center at UC San Francisco.
The 2014 Genitourinary Cancers Symposium is sponsored by the the American Society of Clinical Oncology (ASCO), the American Society for Radiation Oncology (ASTRO), and the Society of Urologic Oncology (SUO).