The trial revealed that colon tumours containing defects in their DNA mismatch repair system are 50% more likely to recur following surgery, compared to tumours where DNA mismatch repair is normal.

In addition, tumours showing mutation of the KRAS gene are more likely to re-grow compared to tumours containing a normal KRAS gene.

The 10-year randomised involved 1913 patients, who were randomised between fluorouracil/folinic acid chemotherapy or observation alone.

According to the study authors, the results strongly support the introduction of DNA mismatch repair testing into routine clinical practice within the NHS.

It also supports further evaluation of BRAF and KRAS gene mutations to predict tumour recurrence.