Genetic screening can improve drug prescribing

PETER LEY, a retired civil servant who lives in London, was diagnosed with colon cancer in 2017. An operation to remove the tumour was successful. But the chemotherapy that followed caused a severe reaction that required a two-week hospital stay and a pause in his cancer treatment.

All that could have been avoided had a simple test been done. The test examines a gene that encodes a liver enzyme called dihydropyrimidine dehydrogenase (or DPD for short). The enzyme breaks down several common cancer drugs. Without it, toxic levels of the drugs build up in the body, sometimes with fatal results. A complete inability to make DPD is rare, but there are four mutations in the DPD-regulating gene that are known to reduce its production. As it turned out, Mr Ley had one of them.