Dr. Hamilton on Using pCR to Classify Risk in HER2+ Breast Cancer

Erika P. Hamilton, MD, director of the Breast Cancer and Gynecologic Research Program and principal investigator at Sarah Cannon Research Institute, discusses the use of pathologic complete response (pCR) as a way to classify risk status in HER2-positive breast cancer.

Other traditional criteria are being used to determine risk status in early-stage HER2-positive breast cancer, such as size and lymph node status, says Hamilton. In May 2019, ado-trastuzumab emtansine (T-DM1; Kadcyla) was approved for use in the adjuvant setting for women with residual invasive disease after neoadjuvant trastuzumab (Herceptin) and chemotherapy. The approval is based on data from the phase III KATHERINE trial.

Notably, the label doesn't mention any of the traditional criteria that have historically been used to determine risk status, says Hamilton. Rather, its indication is based on the fact that the patient didn't have a pCR to neoadjuvant therapy. This provides more flexibility for women who may not be as high risk, and perhaps don't need docetaxel, carboplatin, trastuzumab, and pertuzumab (Perjeta) in the adjuvant setting, concludes Hamilton.