Oestrogen receptors, sites of metastatic disease and survival in recurrent breast cancer

Two hundred and seventy eight patients with advanced breast cancer who had oestrogen receptor (ER) analyses performed on primary or recurrent tumours were studied. Oestrogen receptor (ER) positive (ER ≧ 5 fmole receptor/mg cytosol protein) tumours recurred significantly more commonly in bone and ER negative (ER < 5 fmole receptor/mg cytosol protein) tumours recurred significantly more often in liver and brain. Patients with ER positive tumours had a significantly better survival after relapse. ER analysis of either primary or recurrent tumour gives some indication of the natural history of breast cancer.