A large-scale UK trial has revealed that more than two-thirds of early breast cancer patients flagged as high risk may avoid chemotherapy thanks to a genomic test that predicts tumor recurrence risk more accurately.
- OPTIMA trial included over 4,400 patients with early-stage high-risk breast cancer.
- Prosigna genomic test assesses tumor gene expression to predict recurrence risk.
- 68% of patients safely skipped chemotherapy with similar outcomes to those treated.
What happened
The OPTIMA trial, presented at the 2026 American Society of Clinical Oncology meeting, enrolled more than 4,400 early-stage breast cancer patients in the UK who had tumors considered high risk based on traditional clinical measurements. These patients all had estrogen receptor-positive, HER2-negative cancer types. Researchers used the Prosigna Breast Risk of Recurrence genomic test to analyze tumor tissue and assign a risk score indicating the likelihood of cancer recurrence over the next ten years.
Patients with low-risk Prosigna scores were treated with hormone therapy alone, while those with higher scores received standard chemotherapy. The trial found that the group who skipped chemotherapy experienced outcomes that were closely comparable to those who did receive the treatment. This randomized non-inferiority study demonstrated that the Prosigna test could safely guide treatment decisions, sparing unnecessary chemotherapy for a majority of patients.
Why it feels good
Chemotherapy is well known for causing considerable side effects, including fatigue, long-term heart damage, nerve issues, increased infections, and cognitive challenges. Avoiding these impacts can greatly improve patients’ quality of life during and after cancer treatment. The OPTIMA trial provides a way to identify which patients really benefit from chemotherapy and which do not, reducing exposure to these risks.
Beyond personal health benefits, this genomic approach could transform breast cancer care worldwide. Millions diagnosed annually might avoid chemotherapy if clinical practice incorporates this test, making treatment more precise and less disruptive. This advancement highlights progress in personalized medicine, where therapies are tailored to the biology of each patient’s cancer, not just traditional risk factors.
What to enjoy or watch next
As clinicians and health systems consider adopting the Prosigna test for guiding breast cancer treatment, watch for updated treatment guidelines incorporating genomic risk assessments. Patients facing early-stage breast cancer may soon routinely discuss genomic testing as part of their diagnostic and treatment planning process.
Further research is likely to explore whether similar genomic assays can guide treatment decisions in other cancer subtypes or stages. The encouraging results from OPTIMA support ongoing efforts to reduce overtreatment and improve quality of life for cancer patients globally, marking a promising step forward in cancer care.