Oestrogen receptors and primary breast cancer.

Oestrogen receptor activity has been determined in the primary tumours from 243 patients with breast cancer and the subsequent clinical course of the disease has been followed for one to five years. Patients with oestrogen receptor-negative tumours had significantly shorter disease free intervals and survival times than those with receptor-positive tumours. Patients with large tumours, or with palpable axillary lymph nodes, or with histopathologically proven involvement of axillary lymph nodes also had a poorer prognosis than those with small tumours, impalpable nodes or histopathologically noninvaded nodes. The prognostic value of oestrogen receptor status was independent of these other three indices so that combination of receptor status and node status permitted definition of groups of patients with particularly good and particularly bad prognosis. The independence of these prognostic indices may relate to the possibility that whilst oestrogen receptor status is an index of the intrinsic biological behaviour of the tumour, nodal involvement and tumour size are more likely to reflect the chronological stage in the course of the disease at which the patient presents.