Radiation Plus Short-Term Hormone Therapy Improves Survival of Men with Early-Stage Prostate CancerIn men with intermediate-risk, early stage prostate cancer, short-term treatment to lower male sex hormones given in combination with radiation therapy prolonged overall survival compared with radiation therapy alone, according to an NCI-supported clinical trial. The results of the study were published July 14 in the New England Journal of Medicine.
The trial, which was conducted by the Radiation Therapy Oncology Group (RTOG) at 212 centers in the United States and Canada, enrolled nearly 2,000 patients with localized nonmetastatic prostate cancer and with serum prostate-specific antigen (PSA) levels of less than 20 ng/ml. Patients were randomly assigned to treatment with radiation therapy alone or radiation therapy plus short-term (4 months) androgen deprivation therapy (STADT) using drugs that drastically lowered their natural production of testosterone.
The researchers reported a statistically significant improvement in overall survival after 10 years for participants who received STADT plus radiation compared with those who received radiation therapy alone (62 percent versus 57 percent overall survival).
Men who received radiation therapy plus STADT were also less likely than men who received radiation therapy alone to die of prostate cancer (4 percent versus 8 percent). Benefits of the combined treatment were limited mainly to patients with intermediate-risk disease and were not seen for men with low-risk prostate cancer, the researchers said. (Men with intermediate-risk disease have higher Gleason scores, PSA, and clinical stage values than men with low-risk disease.)
The study included nearly 400 black men, who have a higher prostate cancer risk than white men. Benefits from the addition of STADT were similar in white and black men for 10-year overall survival, prostate cancer-specific mortality, and biochemical failure (i.e., a rise in PSA levels after initially lowered levels due to androgen deprivation therapy).
“This study has important significance for clinical care,” said lead author Dr. Christopher U. Jones, of Radiological Associates of Sacramento, CA. “We now have strong scientific evidence about which patients with early-stage prostate cancer benefit from STADT” added to conventional radiation therapy. But the authors also note that new radiotherapy techniques now make it possible to use higher doses of radiation than were used in this study. A successor RTOG study will investigate the value of adding STADT in men with intermediate-risk disease treated with these new radiation methods.