Four different types of bowel cancer discovered

London: Bowel cancer can be divided into four distinct diseases, each with its own set of biological characteristics, scientists, including one of Indian-origin,  have found. 

The research could allow doctors to treat each type of  bowel cancer differently - and drive the design of distinct  sets of targeted drugs for each type.  Scientists at The Institute of Cancer Research (ICR), London, alongside colleagues at research institutes in the US  and Europe, brought together the world's largest set of data  on bowel cancer in order to classify tumours into the four  groups. 

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 neighbouring tissues. 

They 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. 

Scientists at the ICR and their colleagues found that 87  per cent of bowel cancers could be robustly assigned to one of  the four groups. 

Tumours within the four 'consensus molecular subtypes',  or CMSs, each had a pattern of irregularities that could leave  them vulnerable to the same treatment strategy.  Patients with one particular type of bowel tumour - 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.  Patients with another type, CMS2, had much better  survival rates even if the cancer had relapsed. 

"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," said study co-leader Dr Anguraj Sadanandam, Team Leader in Precision Cancer Medicine  at The Institute of Cancer Research, London. 

"This could allow doctors to pick out those patients with  more aggressive disease and treat them accordingly. 

"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," Sadanandam said. 

The study is published in the journal Nature Medicine.