Oestrogen receptor assay in primary breast cancer: clinical validation and prognostic value

The results of a cytoplasmic oestrogen receptor assay in 134 cases of primary breast cancer are reported. Overall, 57% of primary cancers tested were oestrogen-receptor 'positive' (ER+) and attention is drawn to the need for careful initial handling of tumour tissue, to ensure an accurate assay result. ER+ tumours occurred more often and showed higher assay values in postmenopausal compared with premenopausal women and nine of 12 ER+ tumours responded to hormone manipulation when disease recurred. Follow-up of primary disease confirmed that women with ER+ tumours have a better prognosis with a lower risk of early recurrence than those with ER-tumours. It is suggested that clinical validation of the oestrogen receptor assay should precede routine clinical use.