An ingenious new treatment for advanced prostate cancer, which homes in on tumours to deliver a high-energy burst of radiation to cancer cells, has shown significant benefits to patients in a large-scale clinical trial.

The results of the phase III trial of 921 patients, published in the New England Journal of Medicine, show that treatment with radioactive radium-223 gave men with late-stage prostate cancer an average extra 3.6 months – about 15 weeks – of life.

Men given the treatment lived for an average of 14.9 months, compared with 11.3 months for men given an inert placebo injection.

The trial also showed a meaningful improvement in the patients’ quality of life.

The trial, led by The Royal Marsden NHS Foundation Trust and scientists from The Institute of Cancer Research, London, was so successful that it was stopped early, so that the group of patients receiving the placebo could also take the treatment.

Some 90% of patients with metastatic castration-resistant prostate cancer have bone metastases, which are a major cause of death, disability and decreased quality of life.

The treatment had minimal side-effects in patients with advanced prostate cancer because it ‘homes in’ on tumours in the bone, delivering radiation over a short range and therefore causing little damage to non-cancerous tissue. Radium is taken into growing bone because it has similar chemical properties as calcium.

The trial was funded by companies Algeta and Bayer Pharmaceuticals, who own the licence for the therapy, which has the brand name Xofigo.

Over 40,000 men are diagnosed with prostate cancer every year in the UK, with 10,000 men dying from their disease. For patients whose prostate cancer has spread to their bones and become resistant to treatment, the current last line of treatment is a chemotherapy drug called docetaxel. But many patients are not given docetaxel because they are too frail for the side effects, or they refuse it.

Radium 223 is an important treatment because it can be used alongside other treatments for prostate cancer, or it can be used on its own for patients whose condition is too frail for other treatments.

Study leader Dr Chris Parker, Consultant Clinical Oncologist at The Royal Marsden and Reader in Prostate Oncology at The Institute of Cancer Research, said: “Prostate cancer is one of the most common cancers in men and when it spreads, it has a tendency to involve the bones. Although we are starting to see new drugs for late-stage prostate cancer being developed, bone metastases are still often the cause of significant pain, disability and, ultimately, loss of life.

“We’re excited by the prospects for this ingenious new treatment, which takes advantage of the properties of tumours growing within bone to home in and deliver a highly targeted dose of radiation. We were delighted to show that radium 223 allowed many men in our trial to live to see a few extra, precious months. Not only did they live longer, these men had a much better quality of life.

"The study paves the way for radium 223 to be used to extend the lives of more men with advanced prostate cancer.”

Source: ICR