Scientists examine tumour DNA to determine which drugs are most likely to be effective.

People with advanced gastric cancer live slightly longer if their treatments are tailored to the genetics of their tumours than they do when they receive standard chemotherapy.

Gastric cancer is the third leading cause of cancer deaths globally. The genetic profile of gastric tumours can vary widely between patients, suggesting a need for patient-specific therapy. Jeeyun Lee at the Sungkyunkwan University School of Medicine in Seoul and her colleagues conducted a study — the largest of its kind so far — to evaluate whether survival could be improved by choosing treatments specific to the genetic markers in a patient’s tumour.

The team analysed tumour genomes from 715 people with gastric cancer. Researchers assigned study participants to one of ten treatment groups by matching people whose tumours had a set of specific genetic changes with drugs that target those changes. Participants who received a treatment matched to their tumour lived an average of 9.8 months, significantly longer than the 6.9-month average survival of those who received standard chemotherapy.