Prostate radiotherapy can benefit some men whose cancer has spread

22 Oct 2018

Treating the prostate with radiotherapy alongside standard treatment substantially improves survival for some men with advanced prostate cancer, according to results from the STAMPEDE trial, published in The Lancet and presented at the 2018 ESMO Annual Meeting in Munich, Germany yesterday.

These findings are practice changing and will mean radiotherapy, alongside hormone therapy should become the standard of care for some men with advanced prostate cancer.

In this part of the STAMPEDE trial, more than 2,000 men with prostate cancer that had already spread beyond the prostate were randomly split into two groups:

Group A received standard treatment (hormone therapy, plus docetaxel for those men who were recruited in 2016)
Group H received standard treatment (hormone therapy, plus docetaxel for those men who were recruited in 2016) plus radiotherapy to their prostate.

After three years of follow-up, the researchers found that overall, there was no difference in how long men in the two groups lived, on average.

But, for the sub-group of men whose disease had spread less (‘low metastatic burden’) at the time of diagnosis, there was a significant benefit from radiotherapy. After 3 years, 81% of men with low metastatic burden in the radiotherapy group were still alive, compared to 73% of men in the standard treatment group. Radiotherapy also delayed the disease getting worse.

Radiotherapy did not help men whose disease had spread further at the time of diagnosis (high metastatic burden) to live longer.

The proportion of patients reporting having had severe side-effects was very similar between men who had standard treatment plus radiotherapy and those who had standard treatment alone.

Around 7,000 men are diagnosed in the UK each year with prostate cancer that has already spread beyond the prostate.

Dr Chris Parker, lead researcher of the study and based at the Royal Marsden, said: “Our results show a powerful effect for certain men with advanced prostate cancer. These findings could and should change standard of care worldwide.

“Until now, it was thought that there was no point in treating the prostate itself if the cancer had already spread because it would be like shutting the stable door after the horse has bolted. However, this study proves the benefit of prostate radiotherapy for these men. Unlike many new drugs for cancer, radiotherapy is a simple, relatively cheap treatment that is readily available in most parts of the world.”

STAMPEDE is the largest prostate cancer treatment trial ever, with more than 10,000 men taking part. The trial, which continues to recruit new men, has an innovative multi-stage, multi-arm design, which was developed and run by the MRC Clinical Trials Unit at UCL. The multi-arm multi-stage or “MAMS” design, which was developed by the MRC CTU at UCL, allows several treatments to be assessed against a single control arm, and for new treatments to be added to the trial as it progresses.

Results from STAMPEDE have already shown adding two different drugs to standard hormone therapy (abiraterone and docetaxel) can improve survival for men with prostate cancer.

Max Parmar, Director of the MRC CTU at UCL, said: “STAMPEDE is changing the face of prostate cancer research because the scale and adaptive nature of the study means that a number of different treatment options can be investigated rapidly and in parallel and new treatments to be tested can be added. This is enabling scientists to get results much more quickly than they usually would. More data will come out in subsequent years, because of the innovative design of the trial. This shows us the importance of investing in more adaptive trials like STAMPEDE to help us make similar progress in the treatments of other diseases such as Alzheimers and TB.”

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