Should Liver Metastases of Breast Cancer Be Biopsied To Improve Treatment Choice?

Abstract

Abstract Background: Decision making on systemic treatment of women with metastatic breast cancer is based on features like estrogen receptor (ER), progesterone receptor (PgR), and HER2 status assessed on the primary tumor. We evaluated the concordance of receptor status between primary tumor and liver metastases and estimated the potential change of these pathological features and its impact on treatment choice.Materials and methods: We retrospectively analyzed a database including ultrasound guided liver biopsies performed from 1995 to 2008. All tissue samples, both from primary tumor and liver metastases, were analyzed for ER, PgR and HER2 status. Clinical and biological data were obtained from medical charts (including treatments before and after liver biopsy). Differences between proportions were evaluated using the Pearson chi-square test.Results: We identified 215 consecutive patients with matched primary and liver tissue samples. Median time from primary diagnosis to liver biopsy was 4.1 years (range 0-18.3 years). Changes in ER status were observed in 38/215 patients (17.7%). 15/47 patients (31.9%) changed from ER negative to positive and 23/168 patients (13.7%) changed from ER positive to negative [p= 0.0038]. Changes in PgR status were observed in 111/215 patients (51.6%). 16/74 patients (21.6%) changed from PgR negative to positive and 95/141 patients (67.4%) from PgR positive to negative [p <0.0001]. 11/41 patients (26.8%) changed from ER and PgR negative to ER or PgR positive [Group A] and 25/174 patients (14.4%) changed from ER or PgR positive to ER and PgR negative [Group B] [p=0.054]. In the Group A the treatment of 4/11 patients (36.4%) was changed after biopsy: 2/4 started endocrine treatment (HT) and 2/4 stopped it. In Group B the treatment of 16/25 patients (64%) was changed after biopsy: 15/16 stopped HT. Changes in HER2 status were observed in 19/131 patients (14.5%): 5/93 patients (5.4%) changed from HER2 negative to positive and 14/38 patients (36.8%) changed from HER2 positive to negative [p= <0.0001]. In this group 5/5 patients started a trastuzumab containing treatment after biopsy.Conclusions: There was a substantial discordance in receptor status between primary tumor and liver metastases, which led to change in therapy for 21.8 % of patients. Biopsy of metastases for reassessment of biological features should be considered in all patients when safe and easy to perform, since it might impact treatment choice for many. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6003.