Prognosis and endocrine therapy selection for patients with low hormone receptor‑positive breast cancer following neoadjuvant chemotherapy: A retrospective study of 570 patients in China

The 2010 American Society of Clinical Oncology guidelines have reduced the immunohistochemistry cut-off value for determining estrogen receptor b positivity from 10 to 1% of stained cells in breast cancer. In clinical practice, low-hormone receptor positive (low HR+) tumors are classified in the luminal subtype, although they exhibit aggressive features and poor prognosis. Information regarding the prognosis of patients with breast cancer following treatment with optimal endocrine therapy and neoadjuvant chemotherapy (NAC) is currently lacking. In the present study, the differences in clinical characteristics and survival of patients with breast cancer were compared among those with low and high HR+ breast cancer who received NAC. Furthermore, the effects of different types of endocrine therapies on the prognosis of patients with breast cancer were compared. The study population comprised patients with primary breast cancer who were treated at the Zhejiang Cancer Hospital between January, 2007 and December, 2017. Patients were divided into three groups based on the results of immunohistochemistry: HR+ (positive staining >10%), HR- (positive staining <1%) and low HR+ (positive staining 1–10%). The low HR+ group was further divided into three subgroups according to the different endocrine therapies administered: Tamoxifen, aromatase inhibitor or no treatment. Among the 570 patients included in the present study, 60 (10.53%) patients had low HR+ tumors. With a median follow-up of 48.98 months, patients with low HR+ tumors had reduced survival rates compared with those with HR+ tumors. Furthermore, the pathologic complete response rate (pCR) of patients with low HR+ was comprised between pCR from patients with HR+ and pCR from patients with HR- following NAC treatment. In addition, no significant difference in the overall prognosis was observed among patients with low HR+ following treatment with different endocrine therapies. Subsequently, patients in the low HR+ group were more likely to benefit from NAC compared with patients in the HR+ group. Intensive endocrine therapy may therefore improve the prognosis of patients with breast cancer and low HR+; however, further investigation is required.