Short Androgen Suppression and Radiation Dose Escalation in Prostate Cancer: 12-Year Results of EORTC Trial 22991 in Patients With Localized Intermediate-Risk Disease

EORTC Radiation Oncology Group, Michel Bolla*, Anouk Neven, Philippe Maingon, Christian Carrie, Ana Boladeras, Demetrios Andreopoulos, Antoine Engelen, Santhanam Sundar, Elzbieta M. van der Steen-Banasik, John Armstrong, Karine Peignaux-Casasnovas, Jihane Boustani, Fernanda G. Herrera, Bradley R. Pieters, Annerie Slot, Amit Bahl, Christopher D. Scrase, David Azria, Jan JansaJoe M. O'Sullivan, Alphonsus C.M. Van Den Bergh, Laurence Collette

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

PURPOSE: The European Organisation for Research and Treatment of Cancer (EORTC) trial 22991 (NCT00021450) showed that 6 months of concomitant and adjuvant androgen suppression (AS) improves event- (EFS, Phoenix) and clinical disease-free survival (DFS) of intermediate- and high-risk localized prostatic carcinoma, treated by external-beam radiotherapy (EBRT) at 70-78 Gy. We report the long-term results in intermediate-risk patients treated with 74 or 78 Gy EBRT, as per current guidelines.

PATIENT AND METHODS: Of 819 patients randomly assigned between EBRT or EBRT plus AS started on day 1 of EBRT, 481 entered with intermediate risk (International Union Against Cancer TNM 1997 cT1b-c or T2a with prostate-specific antigen (PSA) ≥ 10 ng/mL or Gleason ≤ 7 and PSA ≤ 20 ng/mL, N0M0) and had EBRT planned at 74 (342 patients, 71.1%) or 78 Gy (139 patients, 28.9%). We report the trial primary end point EFS, DFS, distant metastasis-free survival (DMFS), and overall survival (OS) by intention-to-treat stratified by EBRT dose at two-sided α = 5%.

RESULTS: At a median follow-up of 12.2 years, 92 of 245 patients and 132 of 236 had EFS events in the EBRT plus AS and EBRT arm, respectively, mostly PSA relapse (48.7%) or death (45.1%). EBRT plus AS improved EFS and DFS (hazard ratio [HR] = 0.53; CI, 0.41 to 0.70; P < .001 and HR = 0.67; CI, 0.49 to 0.90; P = .008). At 10 years, DMFS was 79.3% (CI, 73.4 to 84.0) with EBRT plus AS and 72.7% (CI, 66.2 to 78.2) with EBRT (HR = 0.74; CI, 0.53 to 1.02; P = .065). With 140 deaths (EBRT plus AS: 64; EBRT: 76), 10-year OS was 80.0% (CI, 74.1 to 84.7) with EBRT plus AS and 74.3% (CI, 67.8 to 79.7) with EBRT, but not statistically significantly different (HR = 0.74; CI, 0.53 to 1.04; P = .082).

CONCLUSION: Six months of concomitant and adjuvant AS statistically significantly improves EFS and DFS in intermediate-risk prostatic carcinoma, treated by irradiation at 74 or 78 Gy. The effects on OS and DMFS did not reach statistical significance.

Original languageEnglish
Pages (from-to)3022-3033
Number of pages12
JournalJournal of clinical oncology : official journal of the American Society of Clinical Oncology
Volume39
Issue number27
Early online date26-Jul-2021
DOIs
Publication statusPublished - 20-Sep-2021

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