Widely used DNA test can spare colon cancer patients unnecessary chemotherapy

A DNA test that is already widely used can also predict which patients with metastatic colorectal cancer will not benefit from life-prolonging chemotherapy, the one with trifluridine/tipiracil (FTD/TPI). That is a medicine administered twice a day in tablet form.

Researchers at the Antoni van Leeuwenhoek hospital and the Netherlands Cancer Institute have demonstrated this. “In the short term, the findings may already lead to a careful selection of patients with tumors that are refractory to this chemotherapy so that they are spared unnecessary treatment with unpleasant side effects,” the researchers explained.

It involves people with a “KRAS G12 mutation” in the DNA of their tumor. In these patients, one specific “letter” has changed in the 3 billion code letters that the tumor DNA counts. The mutation is common in people with colon cancer. About a quarter of all patients have this mutation in their tumor’s DNA.

“The results of our study are so strong that in our view, adjustment of the guideline is desirable to ensure that people with G12 mutations no longer receive this chemotherapy. You then save patients unnecessary suffering,” said the scientists. They hope such a test method can also show the effect of other forms of chemotherapy in the future.