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RTOG 9910 Trial Shows No Benefit of Longer Androgen Suppression Before Radiotherapy for Localized Prostate Cancer

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Key Points

  • No differences were observed in disease-specific or overall survival.
  • No differences were observed in incidence of locoregional progression, distant metastasis, or PSA-based progression.

As reported by Pisansky et al in the Journal of Clinical Oncology, the Radiation Therapy Oncology Group (RTOG) 9910 trial showed no benefit of extending the duration of pre–radiation therapy androgen suppression on survival or disease control among patients with localized prostate cancer.

Study Details

In the open-label trial, 1,579 men with intermediate-risk prostate cancer were randomly assigned between February 2000 and May 2004 to receive 8 weeks (n = 752) or 28 weeks (n = 737) of androgen suppression followed by radiotherapy with an additional 8 weeks of concurrent androgen suppression. The trial was designed to detect a 33% reduction in the hazard of prostate cancer death in the 28-week group.

Median age was 71 years in both groups, most patients were white (79%–81%), and most had T1b-c tumor stage (50%–52%), Gleason score of 7 (62%–63%), serum prostate-specific antigen (PSA) < 10 ng/mL (47%), National Comprehensive Cancer Network intermediate risk (84%), no prior androgen suppression (74%–77%), and no nodal radiotherapy (83%-85%).

No Difference in Survival or Progression

Median follow-up was 9.4 years. Ten-year disease-specific survival was 96% (95% confidence interval [CI] = 94.6%–98.0%) in the 28-week group vs 95% (95% CI = 93.3%–97.0%) in the 8-week group (hazard ratio [HR] = 0.81, P = .45) and 10-year overall survival was 67% (95% CI = 63.0%–70.8%) vs 66% (95% CI = 62.0%–69.9%; HR = 0.95, P = .62). Ten-year cumulative incidence of locoregional progression was 4% vs 6% (HR = 0.65, P = .07), 10-year cumulative incidence of distant metastasis was 6% vs 6% (HR = 1.07, P = .80), and 10-year cumulative incidence of PSA-based recurrence was 27% vs 27% (HR = 0.97, P = .77).

The investigators concluded: "Extending [androgen suppression] duration from 8 weeks to 28 weeks before radiotherapy did not improve outcomes. A lower than expected prostate cancer death rate reduced ability to detect a between-group difference in disease-specific survival. The schedule of 8 weeks of [androgen suppression] before radiotherapy plus 8 weeks of [androgen suppression] during radiotherapy remains a standard of care in intermediate-risk prostate cancer.”

Thomas M. Pisansky, MD, of the Mayo Clinic, is the corresponding author for the Journal of Clinical Oncology article.

The study was supported by grants from RTOG, Community Clinical Oncology Program, and National Cancer Institute. For full disclosures of the study authors, visit jco.ascopubs.org.

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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