Survival results from STAMPEDE, radiotherapy for prostate cancer

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Published: 21 Oct 2018
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Dr Chris C. Parker - The Royal Marsden, London, UK

Dr Chris C. Parker speaks at the ESMO 2018 congress about results from the STAMPEDE trial for men with metastatic prostate cancer.

To watch his interview with ecancer click here.

Thank you very much, good morning everybody. This afternoon I’ll be presenting the results from the STAMPEDE trial looking at prostate radiotherapy in men with metastatic prostate cancer. Here are my disclosures.

Until now men with metastatic prostate cancer have always been treated with drugs and it was thought that if the cancer had spread elsewhere then there was no point in treating the prostate itself with surgery or radiotherapy, it’s just too late. We have an expression in England – there’s no point shutting the stable door after the horse has bolted, I don’t know if that translates but that’s the idea. However, in animal models of metastatic cancer it has been shown that if you treat the primary tumour then the metastases actually slow down and the animals live longer. So we wanted to ask the question is the same thing true of men with metastatic prostate cancer in the clinic. In particular, we hypothesised that if there was a benefit for treating the prostate it was likely to be greater in men who had a low metastatic burden rather than many, many metastases.

So this is the trial design, it’s men with newly diagnosed metastatic prostate cancer. There were over 2,000 of them in the trial and they were randomised either to receive standard drug treatment only or standard drug treatment plus prostate radiotherapy. This is the only results slide I’m going to show you but it’s the key findings. Patients with low burden disease are those in whom the cancer has spread just to nearby bones or to lymph glands and patients with high burden disease are those in whom the cancer has spread to distant bones or to other organs such as the liver. If we look at the high burden patients first of all there’s no survival benefit to prostate radiotherapy, the curves are overlying one another. On the other hand, in patients with low burden disease there’s a significant survival benefit for prostate radiotherapy and so the hazard ratio is 0.68, so in other words a 32% improvement in survival. It’s highly significant, statistically speaking, and the absolute improvement in survival at three years is from 73% to 81%, so the absolute benefit is 8%. It’s perhaps also worth saying that prostate radiotherapy is a simple treatment, it’s very well tolerated and it’s widely available in any cancer centre throughout the world.

So this summarises our findings. Prostate radiotherapy did not improve overall survival in the whole trial population but it did improve survival in those with a low metastatic burden and it was well tolerated. So the implications, going forward prostate radiotherapy should now be a standard treatment option for men with newly diagnosed metastatic prostate cancer with a low metastatic burden.

The second point is an interesting one and it relates to men with regional nodal metastases but not metastatic disease. These men were not included in our trial. However, if prostate radiotherapy improves survival for men with distant metastases we can be very confident that it would improve survival for men with regional nodal disease. There aren’t any trials addressing that question and currently many of these men receive drug treatment alone. So going forward prostate radiotherapy should be a standard treatment for these men as well.

Then lastly we’ve proven the principle in prostate cancer that treating the primary can improve survival in men with metastatic disease and so this concept should now be tested in patients with oligometastatic disease, low burden metastatic disease, from other malignancies. Thank you very much.