Dr Nanda on HER2-Low Status Testing in Early-Stage Breast Cancer

Rita Nanda, MD, associate professor, medicine, director, Breast Oncology Program, University of Chicago, UChicago Medicine, discusses the importance of testing for HER2-low status in patients with early-stage breast cancer.

Depending on the cancer center, the approach to HER2 testing has been limited to fluorescence in situ hybridization without incorporating immunohistochemical (IHC) analysis, Nanda begins. This practice often necessitates revisiting patients with unknown HER2 IHC status by performing IHC or conducting new biopsies on primary breast tumors, she says. It is common for patients to undergo a new biopsy when experiencing a recurrence following early-stage breast cancer, according to Nanda. The thorough examination of all tumor samples for HER2-low status is essential, particularly when considering the potential benefit of HER2-low–directed therapy, she explains.

The current IHC analysis methods may not be optimal for identifying patients eligible for treatment with fam-trastuzumab deruxtecan-nxki (Enhertu; T-DXd), she says. Ongoing studies and the exploration of different biomarkers hold promise in refining patient selection criteria, Nanda explains. There remains considerable interest in further elucidating whether expanding access to testing or adopting alternative HER2 testing methodologies could better identify patients who would derive substantial benefit from this life-extending therapy, Nanda elucidates.

Accurately identifying HER2 status is vital, as it directly influences treatment decisions and patient outcomes, she expands, adding that accurate assessment is critical for determining the potential efficacy of targeted therapies, such as T-DXd, in patients with HER2-low breast cancer. Enhancing diagnostic capabilities through the exploration of novel biomarkers and testing methodologies is essential for optimizing patient care and ensuring that eligible patients receive appropriate and effective treatments, Nanda notes.

Furthermore, ongoing efforts are aimed at refining the breast cancer field’s understanding of HER2 expression patterns and patient responses to targeted therapies, she continues. These endeavors are driven by the goal of expanding access to life-extending treatments for a broader population of patients with HER2-low breast cancer, Nanda concludes.