Does the oestrogen receptor concentration of a breast cancer change during systemic therapy?

Ra Hawkins,U Chetty,Al Tesdale,Pa Levack,Apm Forrest,Edc Anderson

doi:10.1038/bjc.1990.196

Abstract

The effect of systemic therapy on tumour oestrogen receptor (ER) concentration has been studied in 88 patients with large, operable, primary tumours (total 89) of the breast. In 26 patients, tumour was not available for study on one occasion (usually post-treatment). Forty-five patients were treated initially by endocrine therapy but, of these, 13 who had failed to respond went on to receive chemotherapy also. Seventeen patients with low concentrations of ER (less than 20 fmol mg-1 protein) were treated directly by chemotherapy. Patients underwent an incisional biopsy for confirmation of diagnosis and determination of pre-treatment ER by radioligand binding assay, followed by systemic therapy for 3 months (or 6 months for both endocrine and cytotoxic therapies). Response was assessed clinically and mammographically before mastectomy. ER concentration was then determined in the post-treatment tumour specimen. No significant change in ER concentration was seen in any treatment group except when the patients had received tamoxifen; there, receptor concentration fell to very low levels, presumably due to interference with the assay. There was no relationship between tumour response to systemic treatment and change in ER concentration. It is concluded that changes in ER concentration are unlikely to play a major role in the early response of breast tumours to systemic therapy.

Highlights

We have previously reported the treatment of patients with large operable breast cancers by primary systemic therapy, with direct observation of response and eradication of residual local disease by planned locoregional surgery 3-6 months later (Forrest et al, 1986; Anderson et al, 1989)
Changes in ER concentration according to type of systemic therapy
The changes in individual tumours varied considerably, even within one treatment group (Figure 1), there was no significant change in receptor concentration in patients treated by surgical or medical oophorectomy, aromatase inhibitors, chemotherapy or both cytotoxic and endocrine therapies

Summary

Methods

We attempted to measure oestrogen receptor concentration, both before and after systemic therapy, in patients with large (mean clinical diameter >4 cm) operable (T2 or T3, No or N1 and MO) cancers of the breast: one patient had two tumours and there was a total of tumours. In 26 patients, the tumour specimen was inadequate (see below) on one or more occasions: this left patients (with tumours) for study. These patients form part of a larger series which will be reported in full elsewhere (Anderson et al, in preparation). The mean age of the population was 53 years (range 34-69)

Results

Discussion

Conclusion