Extended field (periaortic) irradiation in carcinoma of the prostate--analysis of RTOG 75-06.

From 1976 to 1983 the Radiation Therapy Oncology Group conducted a study of extended field (periaortic) irradiation in carcinoma of the prostate. Eligible patients were those with clinical Stage C tumor with or without evidence of pelvic lymph node involvement and also those with Stage A-2 and B with evidence of pelvic lymph node involvement. The stratification criteria included histological grade, clinical stage, absence or presence of hormonal manipulation, and method of lymph node evaluation (lymphangiogram vs. laparotomy vs. no nodal evaluation). The patients were randomized to either receive pelvic irradiation followed by a boost to the prostate or pelvic and periaortic irradiation followed by a boost to the prostate. The prescribed daily dose was 180-200 rad to a total midplane dose to the regional lymphatics to 4000-4500 rad. The prostatic boost target volume was to receive additional 2000-2500 rad bringing the total dose to that area to a minimum of 6500 rad. A total of 523 analyzable patients have been accessioned to the protocol. Four hundred forty-eight of these are known to have received treatment per protocol. Median follow-up is 4 years and 3 months. The analyzable patients were evaluated for the incidence of distant metastases, NED survival and survival as a function of treatment arm. No statistically significant differences between the treatment arms could be documented. Similarly, no significant difference between treatment arms could be documented within a number of subpopulations such as those characterized by a particular grade, hormonal status, stage, age, acid phosphatase level, etc. The results of the study revealed no apparent benefit of elective periaortic irradiation in patients with detectable disease confined to the pelvis.

RCT Entities:   Population Interventions Outcomes