Advanced radiotherapy technology could safely deliver curative treatment for some prostate cancer patients in just one or two weeks, according to new research published today. This is a significant reduction from the current standard of care, which is one to two months and the first time such a short timeframe of treatment has been investigated in a phase III trial.
In the PACE-B trial, published today (Tuesday 17 Sept 23:30 UK BST) in The Lancet Oncology, researchers at The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, London, used ultra-hypofractionated stereotactic body radiotherapy (SBRT) to deliver five higher doses of radiation to patients over one to two weeks. Researchers found in the three months after treatment, side effects were no worse when compared with patients who had conventional therapy with more moderate doses over a much longer period of time.
They are still awaiting data on long-term side effects and overall efficacy; in the UK the treatment technique currently only available in a trial setting.
SBRT allows clinicans to target tumours to sub-millimetre precision. Greater accuracy reduces the chance of damaging surrounding healthy tissue, which can lead to urinary and rectal side effects such as more frequent or urgent urination and diarrhoea. In the PACE-B study researchers wanted to understand whether they could safely increase the dose of this targeted radiation, and so reduce the number of treatments required, or if this carried a risk of worse toxicity. When treating patients, clinicians have to consider whether the higher doses in a shorter time period is the best option; the potential side effects are a critical factor in making this decision.
847 patients with prostate cancer were randomised to two groups. 432 patients were allocated the current standard of care receiving moderate hypofractionation radiotherapy (CFMHRT) for either 39 doses over seven/eight weeks, or 20 doses over four weeks. 415 patients were allocated ultra-hypofractionated SBRT, receiving five doses of treatment over one or two weeks. For both groups of patients, 90 per cent of whom had intermediate risk prostate cancer, this was intended to be curative treatment with no further treatment planned.
Patients on the control arm were assessed every other week, and on the SBRT arms assessed after the final dose day, and weeks two, four, eight and twelve after the end of treatment. Researchers incorporated both assessments by clinicians and questionnaires completed by patients. They found patients in both groups had similar levels of side effects over the three months after treatment. They also found side effects in both groups were less overall than had been previously published.
