Chemoendocrine Compared With Endocrine Adjuvant Therapies for Node-Negative Breast Cancer: Predictive Value of Centrally Reviewed Expression of Estrogen and Progesterone Receptors—International Breast Cancer Study Group

Abstract

Low levels of ER and PgR are predictive of the benefit of adding chemotherapy to endocrine therapy. Low PgR may add further prediction among pre- and perimenopausal but not postmenopausal patients whose tumors express ER.

Fractionated evaluation of immunohistochemical hormone receptor expression enhances prognostic prediction in breast cancer patients treated with tamoxifen as adjuvant therapy

“…However, both fractionated ER and PR in the present study were shown to display a bimodal distribution, with substantial proportions at F scores of 0 (ER: 30.8%; PR: 29.8%) and 5 (ER: 46.6%; PR: 39.4%) ( Table 1). The distribution was consistent with several previous studies of ER and PR expression measured by immunohistochemical assay (Collins et al, 2005;Nadji et al, 2005;Stendahl et al, 2006;Badve et al, 2008;Viale et al, 2008). Despite the bimodal distribution of ER and PR expression, the present study clearly demonstrates that fractionated ER and PR scores predict a patient's prognosis more accurately than a dichotomized assessment.…”

“…The study by Viale et al (2008) demonstrated a gradually decreasing benefit to adding chemotherapy to endocrine therapy with increasing ER and PR expression fractions when compared with endocrine therapy alone in patients with nodenegative early breast cancer. Stendahl et al (2006) showed that adjuvant tamoxifen could significantly improve survival in premenopausal patients with tumors showing >75% PR positive nuclei.…”

“…Two recent reports by Viale et al (2008) and Stendahl et al (2006) showed that fractionated scoring of ER and PR, defined as assigning scores based on the fraction of cells that were stained positively for ER and PR by IHC, could enhance the prediction of a benefit from adjuvant chemotherapy and/or hormonal therapy. The study by Viale et al (2008) demonstrated a gradually decreasing benefit to adding chemotherapy to endocrine therapy with increasing ER and PR expression fractions when compared with endocrine therapy alone in patients with nodenegative early breast cancer.…”

Increasing steroid hormone receptors expression defines breast cancer subtypes non responsive to preoperative chemotherapy

“…Previous studies showed a different pattern of response to chemotherapy according to the degree of steroid hormone receptors. In particular, no or limited benefit from the addition of chemotherapy to endocrine therapy was observed in pre-and postmenopausal women with tumors with high expression of ER [14,15]. Also the higher expression of PgR was correlated in previous studies with a lower degree of response to adjuvant chemotherapy and higher response to endocrine treatment [15,16].…”

“…The cutoff of 50% of positive cells for ER and PgR used for defining highly endocrine responsiveness was arbitrarily selected according to the results of retrospective analysis of several trials (SWOG Intergroup 0100, IBCSG trials VIII and IX) asking the question of the addition of adjuvant chemotherapy to endocrine therapy. In these studies the benefit from the addition of chemotherapy was observed mostly in patients with tumors showing low-intermediate (e.g., \50%) ER and PgR levels [14][15][16].…”