RTOG 94-13 is a phase III study designed to determine the appropriate treatment volume and the optimal way to combine radiation and total androgen suppression for prostate cancer patients who are at greater risk of local/systemic failure.
Patients who have localized adenocarcinoma of the prostate and have an elevated prostate-specific antigen (PSA) level are eligible for the trial, reports Mack Roach, MD, chair of the study. The accrual goal is 1,200 patients.
Patients are being randomized to one of four arms:
- Patients in arm 1 of the study will receive flutamide(Drug information on flutamide) (Eulexin), two 125-mg capsules three times a day, and goserelin(Drug information on goserelin) acetate (Zoladex), monthly for 4 months, beginning 2 months before radiation therapy and continuing until radiation therapy is completed. Radiation treatments include whole pelvis irradiation (to 50.4 Gy) followed by a 19.8-Gy boost to the prostate, to a total dose of 70.2 Gy.
- Patients in arm 2 of the study will receive the same drug therapy as patients in arm 1. However, they will receive radiation therapy to the prostate only (to a total dose of 70.2 Gy).
- Patients in arm 3 will undergo whole pelvis irradiation followed by a boost to the prostate.
- Patients in arm 4 will be treated with radiation therapy to the prostate only.
In both arms 3 and 4, flutamide and goserelin are being given for 4 months once radiation therapy is completed.
"This study allows us to answer the critical question of whether whole pelvis irradiation plus a boost improves the progression free-survival of these patients," says Dr. Roach.
"It also allows us to test the hypothesis that flutamide and Zoladex are more effective if they are administered before and during radiation therapy rather than after radiation treatments," he adds.