Background The incidence of human epidermal growth factor receptor 2 (HER 2) positive breast cancers is rapidly rising worldwide. Although there have been many studies on HER 2 breast cancer treatment and management in recent years, there is a lack of comprehensive reports on the treatment outcomes and disparities within the available literature. Hence, this review aimed to determine the treatment outcomes and their associated factors among patients with HER2-positive breast cancer. Methods A computer-based systematic literature search was conducted using PubMed, EMBASE, and Google scholar databases of articles published from 2000 to 2020. The following key terms (HER 2 positive breast cancer, predictor, determinant, associated factor) and Medical Subject Headings (MeSH) terms (breast neoplasms, treatment outcome, and risk factors) were used to search the English language published articles. Results In most studies, trastuzumab was the most commonly used treatment regimen used in combination with chemotherapeutic agents. Generally, most of the studies (15 studies) showed that the overall survival outcome was relatively higher after treatment among HER2 positive breast cancer patients. Nonetheless, two studies showed that the absence of significant change in the overall survival despite adequate treatment was given to the study participants. In addition, three studies demonstrated a partial response after treating HER2-positive breast cancer patients. Conclusion Generally, the overall survival outcome was relatively higher after treatment among HER2 positive breast cancer patients. The addition of trastuzumab in most of the studies has shown improvement in the overall survival and the disease-free survival rate of the study patients.
Validation of the American Joint Committee on Cancer new prognostic stage groups for HER2-positive breast cancer patients treated with adjuvant chemotherapy and trastuzumab in the prospective ShortHER trial