The impact of estrogen receptor (ER), progesterone receptor (PR), and HER-2 receptor status on treatment of patients with advanced breast cancer.

Abstract

e11580 Background: There are many variables that affect treatment options and outcomes in advanced breast cancer. The expression of ER, PR and HER2 are key in determining prognosis and management. The traditional management of breast cancer did not involve biopsy of metastatic sites. Recent studies indicate that, in a significant number of patients, there is a change in receptor status in the metastasis, and this may alter treatment. There have been many retrospective studies looking at the change in the ER/PR status of the metastatic site. Change in treatment as a result has been less of a focus. Our objective is to document the likelihood of a change in receptor status and the impact of this on treatment. Methods: This is a single center retrospective chart review. Ethics approval has been obtained through Memorial Univeristy of Newfoundland. The Dr. H. Bliss Murphy Cancer Centre database was used to identify 250 patients in Newfoundland who were diagnosed with metastatic breast cancer between January 2006 and November 2011. The review includes patients diagnosed with de novo metastases and those who developed metastases following adjuvant treatment. The information we are collecting includes ER, PR, and HER2 status of original tumour, whether metastases were biopsied and the results of the biopsy. We are also documenting all treatments administered. Results: The percentage of patients who underwent biopsy of metastases, the likelihood of change in receptor status and the likelihood of change in treatment will be calculated. Approximately half of the charts that met our criteria have been reviewed. Of those 125 patients, 35 had a biopsy specimen analyzed for ER/PR and HER2 status. 6 of these 35 patients had a change in their hormone receptor status, and 3 had a change in their HER2 status. The likelihood of change in treatment recommendations will be determined once all the data have been reviewed. These results will be available for the 2013 ASCO meeting. Conclusions: ER, PR and HER2 status may change from initial diagnosis of breast cancer to metastatic disease. This has important implications for treatment and prognosis, suggesting that biopsy of metastatic sites should be routine.