A groundbreaking genomic test could spare millions of women with breast cancer from undergoing chemotherapy, according to the results of a major international trial that may transform treatment guidelines worldwide. The study, known as Optima and led by University College London, followed more than 4,000 patients with newly diagnosed hormone-positive breast cancer across the UK, Norway, Sweden, Australia, New Zealand, and Thailand.
How the Test Works
The Prosigna test, developed by Veracyte, analyzes the activity of 50 genes in tumor tissue to determine the molecular subtype and provide a score indicating the risk of cancer recurrence within the next decade. This allows doctors to assess whether chemotherapy is likely to be beneficial or if hormone therapy alone would suffice.
Trial Results
Patients were assigned to either standard treatment (chemotherapy plus hormone therapy) or a test-guided group. In the test-guided group, those with low scores received only hormone therapy, while those with high scores received both. After five years, 95% of patients who received chemotherapy and hormone therapy were alive and recurrence-free, compared to 94% who skipped chemotherapy. The nearly identical outcomes suggest that for low-score patients, chemotherapy offers little to no additional benefit.
Impact on Patients
Chemotherapy often causes severe side effects such as hair loss, nausea, fatigue, insomnia, infertility, and cognitive impairment. Avoiding unnecessary chemotherapy can significantly improve quality of life. One trial participant described the relief as feeling "like Christmas." Nine years after diagnosis, she remains healthy and active.
Expert Opinions
Prof. Rob Stein, chief investigator of the trial, stated: "Optima addresses a longstanding challenge in breast cancer care: identifying who truly benefits from chemotherapy and who does not. Our findings show that many patients can safely avoid chemotherapy without compromising outcomes." Prof. Iain MacPherson, co-chief investigator, added: "These results represent a major step forward in delivering more personalized, precise care."
Broader Implications
The findings, to be presented at the American Society of Clinical Oncology meeting in Chicago, could reshape treatment for hormone-positive breast cancer, which accounts for up to 80% of cases globally. While the study included some men, the sample was too small for definitive conclusions. The trial was funded by the National Institute for Health and Care Research, Veracyte, and cancer charities.
