Breast cancer patients with high levels of the human epidermal growth factor receptor 2 have a 77.1 percent five-year survival rate, which is 16.6 percent lower than that of HER2-negative patients, notes Healthline. However, the survival rates for women with stage 1 to 3 HER2-positive breast cancer can be improved by over 30 percent with an FDA-approved drug known as trastuzumab, according to the National Cancer Institute.
The 10-year survival rate for HER2-positive breast cancer patients who combined trastuzumab with chemotherapy treatment improved from 74 to 85 percent, according to a study published in the Journal of Clinical Oncology. The study also found a disease-free 10-year survival rate of 64 percent in patients who were not on trastuzumab compared to 74 percent in those who were. Trastuzumab is sold under the trade name Herceptin.
Up to 70 percent of patients with metastatic HER2-positive breast cancer respond to treatment, but only 7 to 8 percent of patients experience complete remission, explains the New England Journal of Medicine. Treatments, such as trastuzumab, which target the HER2 protein improve the prognosis of HER2-positive breast cancer patients and lead to lengthy remissions that can last for over 15 years.