Correlation of estrogen receptor and pathologic characteristics of invasive breast cancer.

Estrogen receptor (ER) status was correlated with a large number of pathological and clinical characteristics of 178 invasive breast cancers. Positive ER was found to be significantly associated with high nuclear and low histologic grades, absence of tumor necrosis, presence of marked tumor elastosis, and older patients. These pathologic parameters enumerated are either directly or indirectly related to tumor differentiation suggesting that ER represents another index of this latter. Multivariate analyses disclosed that both age and tumor differentiation are associated with the ER status. Well-differentiated tumors were more frequently ER+ in older women. Inclusion of an estimate of tumor necrosis as well as patient age appears to allow for further discrimination of ER status in poorly differentiated lesions. Considerations relative to ER and tumor differentiation provide a possible explanation for the dichotomy of response to adjuvant chemotherapy observed in pre and postmenopausal women.