Clinicopathological Features and Survival for Low ER-positive Breast-cancer Patients

Testing patients for estrogen-receptor (ER) expression has become an important factor in the prognosis and prediction of breast cancer. Many studies have shown that endocrine therapy has no benefit for breast-cancer patients with low ER (ER+) expression, in which the proportion of positively stained cells is 1% to 9%.

The study intended to explore the response to endocrine therapy of ER+ breast-cancer patients and to evaluate the benefits of the clinical use of endocrine therapy for treatment.

The research team designed a retrospective analysis and reviewed the data and survival rates of patients with early breast cancer.

The study took place at the Hebei Breast Disease Clinic at the Fourth Hospital of Hebei Medical University in Shijiazhuang, China.

Eligible participants in the study were 862 patients were diagnosed at and admitted to the clinic with early, nonadvanced breast cancer between January and December 2012.

Based on ER-expression levels, participants were divided into ER negative (ER-), which indicates no positive staining of cells; ER+; and ER positive (ER++)-high expression in which the proportion of positively stained cells is ≥10%. The clinicopathological characteristics and the survival rates of the three groups were compared.

The clinicopathological features were similar for the ER- and ER+ groups. Compared to participants in the ER++ group, participants in the ER+ group: (1) were in an earlier stage, (2) had larger tumors, (3) were more likely to be positive for human epidermal growth factor receptor-2 (HER-2), (4) had a higher expression rate of Ki-67, (5) had a lower progesterone-receptor (PR) expression rate, (6) were more likely to receive chemotherapy, and (7) were less likely to receive endocrine therapy. Regardless of whether a participant received endocrine therapy or not, the seven-year overall survival (OS) between the ER- group and the ER+ group showed no significant difference, but both were in a worse condition than the ER++ group (P = .026).

The current study found that the clinicopathological features of ER+ breast cancers were different from those of ER++ breast cancers and similar to those of ER-negative breast cancers. The benefits of endocrine therapy for ER+ breast-cancer patients weren't obvious.