80 Gy with long-term ADT improves 10-year PFS in high-risk prostate cancer

Design

Phase 3, open-label RCT

Population

505 men with high-risk prostate cancer on long-term ADT, France

Primary outcome

5-year progression-free survival

Effect

91.4% vs 88.1% at 5 years; 83.6% vs 72.2% at 10 years (HR 0.56)

GETUG AFU 18 randomised 505 men with high-risk prostate cancer at 25 French centres to 80 Gy or 70 Gy external beam radiotherapy, both with long-term androgen deprivation. It was open-label and published in The Lancet Oncology in September.

At median follow-up of 9.5 years, 5-year progression-free survival, the prespecified end point, was 91.4% versus 88.1%. Ten-year progression-free survival, reported post hoc because events were few, was 83.6% versus 72.2% (HR 0.56, 95% CI 0.40 to 0.78). Late grade 3 or worse toxicity was similar (8% vs 7%).

Dose escalation without extra late toxicity is reassuring. But the clear benefit appears at a post hoc time point, and cancer-specific and overall survival benefits are not shown.

• 80 Gy with long-term ADT is a reasonable option for high-risk disease.
• Use image-guided techniques to keep late toxicity low.
• Tell patients the benefit is in biochemical and clinical progression, not proven survival.

Why it matters

It gives long-term randomised support for dose escalation even when ADT is used.

Don't overread it

The 10-year advantage was a post hoc analysis; no survival benefit has been shown.

The statistics, in plain English

The prespecified 5-year comparison showed a small difference. The larger 10-year difference was analysed post hoc, which weakens it because the time point was not chosen in advance. Progression includes PSA rises, which do not always translate into symptoms or death.

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