AN international study by Oxford University scientists and other European institutions has uncovered a correlation between a rare mutation in bowel cancers and a better outcome for patients.

The finding raised the possibility that patients with such tumours may not require chemotherapy after surgery.

The study focused on bowel cancers and examined the presence of mutations in a gene essential for the accurate copying of DNA when cells divide, known as DNA polymerase epsilon (POLE).

As a consequence of the defects in copying their DNA, these tumours accumulate a much higher number of additional mutations than other bowel cancers – a characteristic that may explain an apparently enhanced immune response against them.

Although POLE mutations are uncommon in bowel cancer, only occurring in one to two per cent of all bowel cancer cases, this still translates to 6,000 to 12,000 patients each year in Europe and the United States alone.

Researchers found that bowel cancers with POLE mutations were substantially less likely to recur than other tumours, and this association appeared particularly strong in cases diagnosed at an early stage, for which the benefits of chemotherapy treatment are relatively modest.

However, because most patients included in the study had been treated with chemotherapy, researchers were unable to verify whether the good prognosis was attributable to the POLE mutations alone, or a combination of the latter and chemotherapy.

Prof Ian Tomlinson, chairman of Molecular and Population Genetics at Oxford's Wellcome Trust Centre for Human Genetics, and a senior author of the study, said: "While these results are encouraging, further studies are required before our findings can be used to inform the care of patients.

"We are actively collaborating with our clinical colleagues in the National Cancer Research Network to evaluate the use of this test in the clinic, with the aim of confirming our results and expediting clinical implementation."