Phase III Trial of Long-Term Adjuvant Androgen Deprivation After Neoadjuvant Hormonal Cytoreduction and Radiotherapy in Locally Advanced Carcinoma of the Prostate: The Radiation Therapy Oncology Group Protocol 92–02

TLDR

The RTOG 92‑02 trial randomized patients with locally advanced prostate cancer to receive either short‑term androgen deprivation with radiotherapy or 24 months of long‑term androgen deprivation (goserelin) after a 4‑month pre‑RT course, with prostate doses of 65–70 Gy and pelvic node doses of 44–50 Gy. Long‑term androgen deprivation after radiotherapy improved most efficacy endpoints, and in patients with Gleason 8–10 tumors it significantly increased overall survival (81 % vs 70.7 % at 5 years, P = .044), though it also raised late gastrointestinal toxicity (2.6 % vs 1.2 %, P = .037).

Abstract

Radiation Therapy Oncology Group (RTOG) Protocol 92-02 was a randomized trial testing long-term (LT) adjuvant androgen deprivation (AD) after initial AD with external-beam radiotherapy (RT) in patients with locally advanced prostate cancer (PC; T2c-4) and with prostate-specific antigen level less than 150 ng/mL.Patients received a total of 4 months of goserelin and flutamide, 2 months before and 2 months during RT. A radiation dose of 65 to 70 Gy was given to the prostate and a dose of 44 to 50 Gy to the pelvic lymph nodes. Patients were randomly assigned to receive no additional therapy (short-term [ST]AD-RT) or 24 months of goserelin (LTAD-RT); 1,554 patients were entered onto the study.The LTAD-RT arm showed significant improvement in all efficacy end points except overall survival (OS; 80.0% v 78.5% at 5 years, P =.73), compared with the STAD-RT arm. In a subset of patients not part of the original study design, with tumors assigned Gleason scores of 8 to 10 by the contributing institutions, the LTAD-RT arm had significantly better OS (81.0% v 70.7%, P =.044). There was a small but significant increase in the frequency of late radiation grades 3, 4, and 5 gastrointestinal toxicity ascribed to the LTAD-RT arm (2.6% v 1.2% at 5 years, P =.037), the cause of which is not clear.The RTOG 92-02 trial supports the addition of LT adjuvant AD to STAD with RT for T2c-4 PC. In the exploratory subset analysis of patients with Gleason scores 8 to 10, LT adjuvant AD resulted in a survival advantage.