Multiple simultaneous and sequential estrogen receptor values in patients with breast cancer

Area of Science:

• Oncology
• Endocrinology
• Pathology

Background:

• Estrogen receptor (ER) status is a critical biomarker for guiding endocrine therapy in breast cancer.
• Assessing ER status consistency is vital for accurate treatment selection and monitoring patient response.

Purpose of the Study:

• To evaluate the concordance of estrogen receptor assays in patients with metastatic breast cancer.
• To determine the impact of synchronous vs. sequential assays and intervening therapies on ER status.

Main Methods:

• Analysis of estrogen receptor assay results from 59 women with metastatic breast cancer.
• Comparison of results from simultaneous assays at different metastatic sites.
• Comparison of results from sequential assays, with and without intervening chemotherapy or hormonal therapy.

Main Results:

• High concordance (86%) was observed for simultaneous estrogen receptor assays from various metastatic sites.
• Sequential assays without intervening therapy showed high stability (83.5%) in estrogen receptor status.
• A significant discrepancy (33%) in estrogen receptor values was noted when assays were preceded by chemotherapy or hormonal therapy, often shifting from positive to negative.

Conclusions:

• Estrogen receptor status is generally reliable across synchronous metastatic sites.
• Intervening therapies, such as chemotherapy and hormonal therapy, can alter estrogen receptor status, necessitating re-evaluation.
• Changes in estrogen receptor status post-therapy, particularly from positive to negative, have implications for subsequent treatment strategies.