Prostate cancer: spare radiotherapy after surgery

Men with prostate cancer can be spared radiotherapy after surgery, according to late breaking results of the RADICALS-RT trial presented by Prof. Chris Parker (The Royal Marsden NHS Foundation Trust and Institute of Cancer Research, UK), as well as a supportive meta-analysis of 3 trials.

The study answered a longstanding question about whether the benefits of radiotherapy after surgery outweigh the side-effects. RADICALS-RT enrolled 1,396 patients after surgery for prostate cancer from the UK, Denmark, Canada, and Ireland. Men were randomly allocated to postoperative radiotherapy or the standard approach of observation only, with radiotherapy kept as an option if the disease recurred.

At a median follow-up of 5 years, progression-free survival was 85% in the radiotherapy group and 88% in the standard care group (HR 1.10; 95% CI 0.81–1.49; P=0.56). Self-reported urinary incontinence was worse at 1 year in 5.3% of patients receiving radiotherapy compared with 2.7% who had standard care (P=0.008). Radiation Therapy Oncology Group (RTOG) grade 3/4 urethral stricture was reported at any time in 8% vs 5% of the radiotherapy and standard care groups, respectively (P=0.03). Longer follow-up is needed to report on survival and on the primary outcome of freedom from distant metastases at 10 years.

The findings were confirmed in a collaborative meta-analysis, presented by Dr Claire Vale (University College London, UK) [2]. The ARTISTIC collaboration meta-analysis included 3 randomised trials comparing adjuvant radiotherapy with early salvage radiotherapy following prostatectomy for men with localised prostate cancer: RADICALS, GETUG-AFU 17, and RAVES. The analysis was planned before the results of the trials were known.

The results are based on all 2,151 men included in the 3 trials, of whom 1,074 were randomised to adjuvant radiotherapy and 1,077 men were randomised to early salvage radiotherapy – of those, 395 men (37%) have commenced salvage treatment to date.

The analysis found no evidence that adjuvant radiotherapy improves event-free survival compared with early salvage radiotherapy (HR 1.09; 95% CI 0.86–1.39; P=0.47). Based on these results, the difference in 5-year event-free survival is likely only to be around 1%.

1. Parker C et al. ESMO Congress 2019. Abstract LBA49_PR.
2. Vale CL et al. ESMO Congress 2019. Abstract LBA48_PR.

Posted on 26 November, 20195 August, 2021