Dr Tripathy on the Management of Early-Stage HER2+ Breast Cancer

Debu Tripathy, MD, professor, chairman, Department of Breast Medical Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, discusses current considerations for the treatment of patients with early-stage HER2-positive breast cancer.

The primary consideration in treating patients with HER2-positive breast cancer is the accurate determination of receptor status, which is integral to diagnosis, Tripathy begins. Protocols exist for conducting the biopsy of the surgical specimen, including proper tissue collection, fixation, staining, and interpretation of HER2 status, he states. Furthermore, the interpretation of tumor HER2 status is based on staining intensity and cell count, according to Tripathy. An immunohistochemical (IHC) score of 3+ indicates HER2 positivity, and IHC 2+ cases require fluorescence in situ hybridization (FISH) analysis for confirmation of HER2 positivity, he explains. This is typically based on HER2 copy number and ratio of grading, Tripathy explains. Notably, HER2 1+ IHC status is relevant for specific treatment indications, particularly with drugs such as fam-trastuzumab deruxtecan-nxki (Enhertu), which is approved for the treatment of patients with HER2-low disease, Tripathy says.

Treatment approaches for patients with HER2-positive breast cancer vary based on disease stage at presentation, Tripathy continues. Patients with clinical stage I disease, which is determined via imaging for tumor size and lymph node assessment, typically undergo de-escalated therapy, Tripathy says. This nuanced treatment strategy balances effective treatment with minimizing potential adverse effects, taking into account the extent of disease, Tripathy adds.

HER2 status profoundly influences treatment decisions, guiding the selection of targeted therapies and informing the overall therapeutic approach for patients with breast cancer. Accurate assessment is paramount for optimizing treatment strategies and enhancing patient outcomes in HER2-positive breast cancer management. Therefore, adherence to standardized protocols for HER2 testing is essential to ensure precise determination of receptor status and guide personalized treatment plans tailored to individual patient needs.