[191] Estrogen Receptor Status Is Generally Stable during Disease Progression from Primary to Metastatic Breast Cancer

EY Han, N Sneige, Y Gong. The University of Texas M. D. Anderson Cancer Center, Houston, TX

Background: Accurate assessment of ER status is necessary prior to endocrine therapy for breast carcinoma. Although ER is usually determined on newly diagnosed breast carcinomas, determination of ER status on metastatic breast carcinomas is often requested by oncologists. Whether ER status can change during disease progression or after chemotherapy or hormonal therapy remains controversial.
Design: Breast carcinoma samples from 56 women with known ER status in both primary tumors and paired metastases (30 locoregional and 26 distant metastases) were retrospectively reviewed. Before their metastatic lesions were sampled, 44(79%) patients underwent chemotherapy and 30 (54%) patients received adjuvant hormonal therapy. ER status was measured by immunoperoxidase study either in tissue sections (50 primary tumors and 10 metastatic tumors) or in fine-needle aspiration smears (6 primary tumors and 46 metastatic tumors). ER status was defined as positive if 10% tumor cells demonstrated nuclear staining.
Results: The interval between the diagnosis of the primary tumor and sampling of the paired metastatic tumor ranged between 0-216 months. ER status of primary and metastatic tumors agreed in 52 of the 56 (93%) patients, including 37 (71%) positive tumors and 15 (29%) negative tumors. A discrepancy of ER status was observed in 4 patients, with two having positive status in primary/negative status in metastatic tumors and another 2 having negative status in primary/positive status in metastatic tumors. In 3 of the 4 patients, the ER score of the positivity were 10% (marginally positive). All the metastatic tumors where ER was tested in the four patients were found in locoregional lymph nodes.
Conclusions: ER status in breast carcinoma is generally stable during disease progression. Chemotherapy and/or hormonal therapy do not significantly affect ER status in metastatic diseases.
Category: Breast

Wednesday, March 11, 2009 9:30 AM

Poster Session V # 2, Wednesday Morning