Final 8-Year Analysis of Intergroup Trial Shows Survival Benefit With Addition of Radiotherapy to Androgen-Deprivation Therapy in Prostate Cancer
In the final prespecified analysis of an Intergroup trial (NCIC Clinical Trials Group PR.3/Medical Research Council PR07/Intergroup T94-0110) reported in the Journal of Clinical Oncology, Mason et al found that overall survival and cancer-specific survival at 8 years were significantly greater with the addition of radiotherapy to androgen-deprivation therapy in patients with locally advanced prostate cancer. An interim analysis had shown a 23% reduction in all-cause mortality with radiotherapy plus androgen-deprivation therapy (hazard ratio [HR] = 0.77, P = .033).
Study Details
In the trial, 1,205 patients with T3-4, N0/Nx, M0 prostate cancer or T1-2 disease with either prostate-specific antigen (PSA) level of > 40 µg/L or PSA level of 20 to 40 µg/L plus a Gleason score of 8 to 10 were randomly assigned between 1995 and 2005 to receive lifelong androgen-deprivation therapy alone (n = 602) or with radiotherapy (n = 603). Radiotherapy was given at 64 to 69 Gy in 35 to 39 fractions to the prostate and pelvis or prostate alone.
Overall and Disease-Specific Survival
At median follow-up of 8 years, 465 patients had died, including 205 in the radiotherapy/androgen-deprivation therapy group vs 260 in the androgen-deprivation therapy group, and 199 had died from prostate cancer, including 65 vs 134. Median overall survival was 10.9 years (95% confidence interval [CI] = 10.0–12.8 years) in the radiotherapy plus androgen-deprivation therapy group vs 9.7 years (95% CI = 8.8–10.5 years) in the androgen-deprivation therapy group (HR = 0.70, P < .001). Overall survival at 10 years was 55% vs 49%. The benefit of radiotherapy was maintained on multivariate analysis (HR = 0.74, P = .0011).
Disease-specific survival was significantly improved in the radiotherapy/androgen-deprivation therapy group (HR = 0.46, P < .001), with no evidence of differences in other causes of death between the two groups being observed (P = .58).
Bowel adverse events of grade ≥ 3 were observed in 2 of 589 evaluable radiotherapy/androgen-deprivation therapy patients at 2 years.
The investigators concluded: “This analysis demonstrates that the previously reported benefit in survival is maintained at a median follow-up of 8 years and firmly establishes the role of [radiotherapy] in the treatment of men with locally advanced prostate cancer.”
Malcolm D. Mason, MD, FRCP, FRCF, FSB, of Cardiff University School of Medicine, is the corresponding author of the Journal of Clinical Oncology article.
The study was supported by the National Cancer Institute, Canadian Cancer Society Research Institute, United Kingdom Medical Research Council, and United Kingdom National Cancer Research Network. For full disclosures of the study authors, visit jco.ascopubs.org.
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