Researchers in Southampton have discovered that a longer gap between chemoradiotherapy and surgery can "significantly" reduce the size of bowel tumours.
In a landmark study, experts in critical care at the NIHR Southampton Respiratory Biomedical Research Unit, the cancer sciences unit at the University of Southampton and the Royal Marsden NHS Foundation Trust, found an additional five weeks of recovery before surgery saw the cancer shrink a further 24%.
Currently, standard treatment is an initial session of combined chemotherapy and radiotherapy - which is known as chemoradiotherapy - to reduce the tumour followed by surgery to remove it after a recovery period of around nine weeks.
The team, led by Professor Mike Grocott, a consultant in critical care at University Hospital Southampton NHS Foundation Trust, and Professor Gina Brown, a consultant in gastrointestinal radiology at the Royal Marsden, used magnetic resonance imaging (MRI) scans to assess the size of the tumours nine and 14 weeks after 35 patients had undergone chemoradiotherapy.
They found the tumours continued to shrink, with an average reduction in size of 62% after nine weeks and 86% after 14 weeks.
"At present the time period between these two treatment interventions varies and there has been little evidence to recommend how long it should be," said Prof Grocott, who is also chair of anaesthesia and critical care medicine at the University of Southampton.
"During this study we found a significant additional reduction in tumour size after a further five weeks."
Mr Malcolm West, who is an NIHR-funded academic clinical lecturer in surgery at University Hospital Southampton NHS Foundation Trust and the University of Southampton, added: "This exciting new research supports delaying surgery for longer after chemoradiotherapy in bowel cancer patients to enable surgeons to remove the tumour at the optimal time."
The research was published in the European Journal of Surgical Oncology.