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Adding 6 Months of Androgen Suppression to Radiotherapy Improves Disease-Free Survival in Intermediate- and High-Risk Prostate Cancer

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Key Points

  • Adding short-term androgen suppression to radiotherapy improved biochemical and clinical disease-free survival in patients with intermediate- and high-risk prostate cancer.
  • The benefit of androgen suppression did not appear to differ with the radiation dose or risk group.

In the phase III EORTC 22991 trial reported in the Journal of Clinical Oncology, Bolla et al found that the addition of 6 months of androgen suppression to radiotherapy improved biochemical and clinical disease-free survival in patients with intermediate- and high-risk prostate cancer.

Study Details

In the open-label trial, 819 patients staged as (1) cT1b-c with prostate-specific antigen (PSA) level ≥ 10 ng/mL or Gleason score ≥ 7 or (2) cT2a with no involvement of pelvic lymph nodes and no clinical evidence of metastatic spread and PSA level ≥ 50 ng/mL were randomized to radiotherapy with (n = 410) or without (n = 409) androgen suppression.

Centers opted for one dose of radiotherapy at 70, 74, or 78 Gy. Androgen suppression consisted of two subcutaneous injections of every-3-month depot of goserelin, given on the first day of radiotherapy and 3 months later. Biochemical disease-free survival was the primary endpoint.

Patients had a median age of 70 years; 75% had intermediate-risk disease, and 25% had high-risk disease.

Improved Disease-Free Survival

Median follow-up was 7.2 years. Five-year biochemical disease-free survival was 82.6% in the combination group vs 69.8% in the radiotherapy group (hazard ratio [HR] = 0.52, P < .001). Five-year clinical disease-free survival was 88.7% vs 80.8% (HR = 0.63, P = .001). Exploratory heterogeneity tests indicated no significant interaction of radiotherapy dose or risk group with treatment effect for biochemical or clinical disease-free survival. Overall survival data are not yet mature.

The investigators concluded: “Six months of concomitant and adjuvant [androgen suppression] improves biochemical and clinical [disease-free survival] of intermediate- and high-risk cT1b-c to cT2a (with no involvement of pelvic lymph nodes and no clinical evidence of metastatic spread) prostatic carcinoma, treated by radiation.”

The study was supported by AstraZeneca and Fonds Cancer (Belgium).

Michel Bolla, MD, of Grenoble University Hospital, France, is the corresponding author of the Journal of Clinical Oncology article.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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