A new cancer diagnostic test, marketed by Veracyte and developed by a group of researchers, including UNC geneticist Charles Perou, PhD, has been found to accurately predict whether patients with breast cancer actually need chemotherapy-or if hormone therapy alone can more safely and effectively put them on a path towards remission.
"Support from a new clinical trial has found that more than two-thirds of high-risk patients could be spared chemotherapy without compromising outcomes," said Perou, who is a distinguished professor at the UNC School of Medicine and expert on breast cancer genomics at UNC Lineberger Comprehensive Cancer Center.
Perou conducted some of the essential research that led to the development of the test, which is called Prosigna. In 2005, researchers started working on a genomic test that can identify the patient's breast cancer subtype and estimate the probability of the cancer coming back; one that could be used right in clinic.
Prosigna analyzes tumor samples and uses a machine learning algorithm to put out a score (a Risk of Recurrence, or ROR score) that gives oncologists unique insight into how a patient's cancer may develop or change over time, such as one's risk of their cancer recurring in ten years.
Charles M. Perou, PhD
In 2007, a clinical trial was set up to see if the Prosigna test could safely guide chemotherapy decisions for patients with early-stage, ER-positive HER2-negative breast cancer.
The trial, termed Optimal Personalised Treatment of early breast cancer using Multi-parameter Analysis (OPTIMA) followed more than 4,400 patients across the United Kingdom, Norway, Sweden, Australia, New Zealand and Thailand over twenty years.
Participants were put on a treatment path according to their Prosigna results. Those who received high ROR scores (>60) received chemotherapy followed by hormone therapy, while those with low ROR scores (≤60) received hormone therapy alone.
The results were:
- 68% of patients with clinically high-risk breast cancer could safely forgo chemotherapy entirely. These patients achieved 5-year cancer-free survival rates of 93.7% without chemotherapy, demonstrating that omitting treatment did not compromise overall health outcomes or increase cancer recurrence risk.
- The Prosigna test was equally effective for previously under-studied populations (premenopausal women and those with multiple breast cancer containing lymph nodes) demonstrating that assessing tumor biology, versus clinical factors alone, can guide chemotherapy decisions for more complex cases.
- Highest level of prospective evidence: With 4,429 patients and 4.0-year median follow-up, OPTIMA provided Level 1A evidence, showing that the Prosigna test can accurately predict chemotherapy benefit and guide safe de-escalation across patient populations.
Following the clinical trial and commercialization of the test, oncologists across the United States and the United Kingdom can now order the Prosigna test to predict which high-risk patients can safely avoid chemotherapy and its lasting side effects without compromising outcomes, making a huge impact on patients and the clinicians alike.
"Prosigna owes its success to patients who trusted the study and their physicians, companies providing cutting-edge technologies for molecular testing, and researchers/clinicians turning ideas into diagnostics to improve patient care," said Perou.
Results from the OPTIMA trial were presented on Saturday, May 30 at the 2026 ASCO Annual Meeting in Chicago.
