Researchers at the Institute of Cancer Research (ICR) in London and the Royal Marsden NHS Foundation Trust have developed a new genomic test. This 'prognostic immune biomarker' aims to identify early-stage, estrogen receptor (ER)-positive, HER2-negative breast cancer patients who may not benefit from chemotherapy after surgery, potentially sparing millions from unnecessary treatment. The initial findings were presented at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago.
The test analyzes tumor-infiltrating lymphocytes (TILs) within breast tumors, combining these immune cell markers with clinical factors and a gene expression signature (PAM50 test) that identifies the luminal A subtype. A study involving 3,700 women with this specific type of breast cancer indicated that those with high TIL levels and a low-risk PAM50 score could safely forgo chemotherapy. This approach could potentially spare up to 2.5 million women globally annually from chemotherapy, reducing side effects and healthcare costs.
The research was funded by Breast Cancer Now, The Estée Lauder Companies, and the NIHR Biomedical Research Centre at The Royal Marsden NHS Foundation Trust and the ICR, and was led by Professor Mitch Dowsett. Professor Kristian Helin, Chief Executive of the ICR, stated the test could 'revolutionize treatment decisions'. Further clinical trials are necessary to validate these findings and facilitate the integration of the test into standard clinical practice.
