Breast-Cancer-Specific Mortality in Patients Treated Based on the 21-Gene Assay: A SEER Population-Based Study

A common gene-panel test can help to predict the likelihood of women with breast cancer dying from the disease. Valentina Petkov at the US National Cancer Institute in Maryland and her colleagues studied a form of breast cancer that responds to hormone therapy in more than 44,500 American patients with and without spread to the lymph nodes. At diagnosis, all had taken a genomic test called Oncotype DX, which estimates the likelihood of breast-cancer recurrence on the basis of expression data from 21 genes. The team found that the test’s ‘recurrence score’ was strongly associated with the chance of death from breast cancer — independent of patient age, tumor size and tumor grade. The study provides the best evidence to date that Oncotype DX can be used to predict mortality risk, including for racial minority and other under-represented groups.