In a  meta-analysis of 4,373 patients who had participated in seven randomized controlled phase III trials, there was a relative risk of relapse of 0.74), Emilio Bria, M.D., of the Regina Elena Cancer Institute in Rome said at the European Society of Medical Oncology meeting here.

The absolute benefit was a 10.5% improvement in progression-free survival over radiation alone, Dr. Bria found. That means nine patients need to be treated to provide benefit to one. Although prior studies had suggested that the addition of hormone therapy to radiation therapy in the treatment of these patients improved outcomes, compared with radiation alone, however the magnitude of the benefit was not known. Overall survival was also significantly improved with the addition of hormone therapy by 6.2%. The relative risk of death was 0.84). Cancer-specific overall survival also improved by 4.2%, with a relative risk of death of 0.66 . Thus, twenty-four patients would have to be treated to prevent a cancer-specific death in one patient. Long term hormone therapy was more effective on improving progression free survival (absolute benefit of 12.3%) compared with short term (9.3% benefit).

The reason for the improved outcomes may be due to increased radiosensitization, local reduction of tumor volume, or the reduction of risk of distant recurrence.

The magnitude of benefit with modern radiation therapy regimens may be slightly better than those reported in this study because four of the trials included in the analysis used shorter radiation courses than is currently considered standard, commented Paolo Carlini, M.D., also of the Regina Elena Cancer Institute, who presented the data during the presidential symposium.