Scientists have now revealed that bowel cancer consists of four distinct diseases, each with its own set of biological characteristics. This findings could allow doctors to treat each type of bowel cancer differently - and drive the design of distinct sets of targeted drugs for each type.
Study co-leader Anguraj Sadanandam, team leader in precision cancer medicine at The Institute of Cancer Research, London, said, "Our study has identified four distinct types of bowel cancer, each with a definite set of genetic and biological characteristics, and some of which are more aggressive and more likely to be fatal than others. This could allow doctors to pick out those patients with more aggressive disease and treat them accordingly."
The researchers said, "The study combined data from 3,443 patients with bowel cancer from all over the world to form the largest collection of molecular and clinical data on the disease ever assembled - including genetic mutations, gene activity, immune system activation, cell metabolism, cancer cell type and ability to invade neighboring tissues."
The research team aimed to group bowel cancers using mathematical algorithms that combined all these parameters, in order to improve on various existing attempts to classify types of the disease based on smaller datasets. The scientists found that 87% of bowel cancers could be robustly assigned to one of the four groups.
Tumors within the four 'consensus molecular subtypes', or CMSs, each had a pattern of irregularities that could leave them vulnerable to a treatment strategy. The researchers revealed that patients with one particular type of bowel tumor - CMS4 - were often diagnosed late (stage III and IV), had high levels of spread to other sites in the body, and had significantly worse survival rates than the other types. Study participants with another type, CMS2, had much better survival rates even if the cancer had relapsed.
Sadanandam said, "Ultimately, it could lead to development of new molecular diagnostic tests to diagnose patients by their particular type of bowel cancer, and give them the most effective treatments for that type."
The study was published in Nature Medicine.