Genomic Test Allows 2/3 Breast Cancer Patients to Skip Chemo

A major international clinical trial has found that a genomic test can identify thousands of patients with breast cancer who can safely avoid chemotherapy without compromising their survival. The findings, which will be presented at the American Society of Clinical Oncology's annual meeting in Chicago, represent a significant advance in personalized cancer care.

The OPTIMA trial, led by University College London, involved more than 4,000 newly diagnosed patients over the age of 40 across the UK, Norway, Sweden, Australia, New Zealand, and Thailand. All participants had hormone-sensitive breast cancer, the most common form of the disease, and in most cases, the cancer had spread to nearby lymph nodes, a situation where chemotherapy is routinely recommended after surgery.

Researchers used a test called Prosigna to analyze the activity of 50 genes involved in breast cancer growth within tumor samples. The test generated a score estimating the risk of the cancer returning. Patients with a low score, which accounted for approximately two-thirds of trial participants, were treated with hormone therapy alone, bypassing chemotherapy.

After five years, the survival outcomes for these...