Patients with intermediate risk, localised prostate cancer can be treated as effectively using fewer and higher doses of radiation therapy delivered over five treatment sessions as they can with lower doses delivered over several weeks, according to researchers from The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, London.
Significant reduction in treatment time
Results from the PACE B (Prostate Advances in Comparative Evidence) phase III randomised trial showed that stereotactic body radiotherapy (SBRT) performed as well as standard radiotherapy treatment for people whose prostate cancer had not spread, demonstrating a 96% chance of no disease progression within five years, compared to 95% for conventional radiotherapy.
SBRT, which can be delivered on a CyberKnife or standard radiotherapy machines, allows clinicians to target tumours to sub-millimetre precision. This approach uses advanced imaging and treatment planning techniques to deliver radiation with pinpoint accuracy, minimising damage to surrounding healthy tissue. It delivers five high doses of radiation to patients over one to two weeks, compared to standard radiotherapy, which delivers more moderate doses over a much longer period of time – usually around 20 sessions for patients in the UK, which can take up to one month.
Drawing from 38 centres across the UK, Ireland and Canada, researchers enrolled 874 people who preferred radiation treatment or were unsuitable for surgery. Patients were randomly assigned to receive either SBRT, consisting of five doses over one to two weeks, or standard radiation consisting of 20 doses over four weeks or 39 doses over 7.5 weeks. None of the patients received hormonal therapy.
“For something as serious as a cancer diagnosis, the treatment was incredibly easy”
The trial investigated whether SBRT was non-inferior to conventional radiation for treating people with intermediate risk, localised prostate cancer. Non-inferiority was measured by whether patients remained free of biochemical clinical failure (BCF), defined as an increase in prostate-specific antigen (PSA) levels, distant metastases or other evidence the cancer was returning, or death from prostate cancer.
Five years after treatment, people treated with SBRT had a BCF-event free rate of 95.7% compared to 94.6% for those treated with conventional radiotherapy, demonstrating that SBRT was non-inferior to conventional radiation.
Side effects were low in both groups and at five years not significantly different between treatment arms.
One patient who benefited from the treatment was 64-year-old Alistair Kennedy-Rose, who was diagnosed with prostate cancer in 2014 at his local hospital following a blood test which revealed his prostate-specific antigen levels were raised. Alistair was referred to The Royal Marsden and, after being recruited to the PACE-B trial, was treated with SBRT via CyberKnife.
He said: “When I was diagnosed I had no symptoms at all, so it came as quite a shock. There can be a lot of anxiety following a cancer diagnosis, but just ten days after I was referred to the Royal Marsden, I started SBRT. I still find it unbelievable that five days later I finished my treatment, for something as serious as a cancer diagnosis it was incredibly easy. I haven’t had any side effects and I’ve been able to live my life to the full. I can’t thank The Royal Marsden enough for what they have done for me.”
Source: The Royal Marsden
