New research carried out by the Institute of Cancer Research in London and researchers at the NIHR Biomedical Centre at the Royal Marsden Hospital suggests that bowel cancer is not just one disease but four distinct conditions, each with their own biological characteristics. In conjunction with colleagues in Europe and the US, the team reviewed data on nearly 3,500 bowel cancer patients around the world that enabled them to classify the disease into four sub-groups.
The findings are significant because each underlying type behaves differently. By studying these patterns, researchers hope to be able to target treatments more effectively to the individual types of bowel cancer. The sub-groups are defined by their genetic make-up, each sharing genes that dictate their behaviour. Importantly, this influences how each sub-group responds to particular types of treatment.
One particular sub-group is commonly associated with later diagnosis and, thus, greater incidence of spread to other parts of the body, with poorer survival rates. Another sub-group was found to be less invidious and more successfully treated, even if the cancer subsequently relapsed.
Commenting on the research, Andrew Clayton of the Penningtons Manches clinical negligence team explains: "Although survival rates for bowel cancer have doubled in the last 40 years, it remains the second biggest cause of deaths from cancer in the UK. Early diagnosis is known to be closely associated with successful treatment but patients have been reluctant to come forward. A screening programme for bowel cancer is currently in trial but early indications are that fewer than half of those invited for screening have taken up the offer.
"Current treatments, including chemotherapy, can be noxious in themselves and frequently cause extremely damaging side-effects that are very hard for patients to tolerate. So this news that bowel cancer can now be classified into distinct types is welcome.
“The natural progression of this research is to enable doctors to tailor treatment more effectively according to the patient’s particular type of bowel cancer. Those with one of the less aggressive forms may thus be spared some of the more radical treatment such as chemotherapy."