Study demonstrates effective treatment of localised prostate cancer using higher doses of radiotherapy
Research confirms efficacy of higher and fewer doses of radiotherapy for treatment of localised prostate cancer, conferring benefits to both patients and the NHS.
Treatment times for patients with localised prostate cancer could be reduced by as much as 75 per cent using higher-than-normal doses of radiotherapy, according to a study published in the New England Journal of Medicine.
The study, led by researchers from The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, London, found that people 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.
Results from the PACE-B (Prostate Advances in Comparative Evidence) trial were published this week in the New England Journal of Medicine (NEJM).
The research builds on previously reported data and shows that stereotactic body radiotherapy (SBRT) performed as well as standard radiotherapy treatment for people whose prostate cancer had not spread, demonstrating a five-year 95.8 per cent disease control rate, compared to 94.6 per cent for conventional radiation.
PACE-B 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.
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 (Intensity-Modulated Radiation Therapy, or IMRT), 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.
Five years after treatment, people treated with SBRT had a BCF-event free rate of 95.8 per cent compared to 94.6 per cent for those treated with conventional radiotherapy, demonstrating that SBRT was non-inferior to conventional radiation.
The study showed that side effects were relatively low in both groups. At five years post-treatment, 26.9 per cent of patients who received SBRT experienced grade two or higher side effects affecting the genital or urinary organs, such as urinary frequency and urgency, compared to 18.3 per cent in the conventional group.
The cumulative incidence of late grade two or higher gastrointestinal effects was 10.7 per cent in patients who received SBRT and 10.2 per cent in the conventional group. At five years, 29.1 per cent of men treated with conventional radiotherapy and 26.4 per cent of men receiving SBRT reported erectile dysfunction.
Chief Investigator Professor Nicholas van As, Medical Director and Consultant Clinical Oncologist at The Royal Marsden NHS Foundation Trust, and Professor in Precision Prostate Radiotherapy at The Institute of Cancer Research, London, said: “At The Royal Marsden and the ICR, we are focused on developing smarter, better and kinder treatments for patients across the UK and internationally. Standard radiation treatment is already highly effective and is very well tolerated in people with localised prostate cancer but for a healthcare system and for patients, to have this treatment delivered just as effectively in five days as opposed to four weeks is hugely significant.
“To be able to sit with a patient and say, ‘We can treat you with a low toxicity treatment in five days, and your chance of keeping the cancer at bay for five years is 96 per cent,’ is a very positive conversation to have. We expect our trial to be practice changing and people with intermediate risk prostate cancer should be given the option of SBRT as an alternative to conventional radiation or prostate surgery.”
