ERICA predicts response to tamoxifen in elderly women with breast cancer.

Oestrogen receptor status has been determined by an immunocytochemical assay using fine-needle aspiration samples of primary breast cancers in elderly patients. In a prospective study 56 patients were treated with tamoxifen only. Satisfactory assays were achieved in 49 patients. Disease was controlled by tamoxifen in 32 of 35 (91%) patients with oestrogen receptor positive tumours, compared with only 1 (7%) of 14 who were receptor negative. Immunocytochemical assay on fine-needle aspiration samples is relatively non-invasive and simple to perform, it accurately predicts response to tamoxifen in elderly patients and can be used to select patients for tamoxifen only therapy.