Radiation Plus Hormone Therapy Reduces Prostate Cancer Mortality

Patients with locally advanced prostate cancer typically have surgery or receive antiandrogen therapy with or without radiation treatment, and questions remain about which is the best approach. At the American Society of Clinical Oncology's Genitourinary Cancers Symposium last month, Norwegian researchers presented phase III data that bolster one option: antiandrogen therapy plus radiation.

According to final results from the Scandinavian Prostate Cancer Group Study (SPCG) VII trial, a combination of antiandrogen therapy and radiation cut 10- and 15-year prostate cancer–specific mortality rates by more than half versus treatment with antiandrogen therapy alone. “That's the takeaway point,” says Howard Sandler, MD, chair of radiation oncology at Cedars Sinai Medical Center and member of its Samuel Oschin Comprehensive Cancer Institute in Los Angeles, CA, who was not involved in the study. “It validates that local control with radiation is important at extending life in patients whose prostate cancer is life-threatening.”

The SPCG trial enrolled 875 men in Norway, Sweden, and Denmark between 1996 and 2002, all of whom had been diagnosed with locally advanced disease. Patients were randomized to one of two arms: In the treatment arm, they were given the drug leuprorelin, which dramatically reduces estradiol and testosterone levels, for 3 months, in addition to lifelong treatment with flutamide, which competes with testosterone for binding to androgen receptors, and 8 weeks of localized radiation. The control arm received the same hormone-suppressing therapy but no radiation. According to results published in the Lancet in 2009, after an average of 7.6 years of follow-up, the mortality rate was 12% lower among men who had received the combination treatment, compared with those in the control arm who hadn't received radiation.

The new 10- and 15-year mortality rates, based on an average of 11 years of follow-up, extend that trend. As presented by Sophie Fossa, MD, PhD, a radiation oncologist at Oslo University Hospital in Norway, the mortality rate in the treatment group was 8.3% at 10 years and 12.4% at 15 years, compared to 18.9% and 30.7%, respectively, among controls. According to Sandler, radiation helps to limit metastatic spread from the prostate, which could explain the survival benefit.

Anthony D'Amico, chief of genitourinary radiation oncology at Dana-Farber Cancer Institute and Brigham and Women's Hospital, both in Boston, MA, says the study shows that combining radiation with hormone therapy offers a viable alternative to prostatectomy, which is associated with urinary incontinence.

Moreover, techniques for administering radiation are safer and more effective now than they were when the SPCG trial was launched, Sandler adds. “Men who don't get surgery are sometimes treated with antihormonal treatments alone,” he says. “This study suggests that approach is inadequate.”