Androgen deprivation with radiation therapy compared with radiation therapy alone for locally advanced prostatic carcinoma: a randomized comparative trial of the Radiation Therapy Oncology Group

Abstract

Objectives: Androgen deprivation therapy before and during radiation therapy could, by reducing tumor volume, increase local tumor control, disease-free survival, and overall survival in patients with locally advanced adenocarcinomas of the prostate.

Methods: In a randomized controlled clinical trial, patients with large T2, T3, and T4 prostate tumors, but no evidence of osseous metastasis, were randomized to receive goserelin 3.6 mg subcutaneously every 4 weeks and flutamide 250 mg orally three times daily 2 months before and during the radiation therapy course (Arm I) compared with radiation therapy alone (Arm II). Pelvic irradiation was administered with 1.8 to 2.0 Gy per day to a total dose of 45 +/- 1 Gy followed by a boost to the prostate target volume to a total dose of 65 to 70 Gy.

Results: Of 471 randomized patients, 456 were evaluable, 226 on Arm I and 230 on Arm II. With a median potential follow-up of 4.5 years, the cumulative incidence of local progression at 5 years was 46% in Arm I and 71% in Arm II (P < 0.001). The 5-year incidence of distant metastasis on Arms I and II was 34% and 41%, respectively (P = 0.09). Progression-free survival rates including normal prostate-specific antigen (PSA) levels for 396 patients with at least one PSA recorded were 36% in Arm I and 15% in Arm II at 5 years (P < 0.001). At this time, no significant difference in overall survival could be detected (P = 0.7).

Conclusions: Short-term androgen deprivation with radiation therapy results in a marked increase in local control and disease-free survival compared with pelvic irradiation alone in patients with locally advanced carcinoma of the prostate. Long-term surveillance is required to assess effects on overall survival.