Biomarker discordance: Prospective and retrospective evidence that biopsy of recurrent disease is of clinical utility

摘要

Abstract. Prospective studies of biomarker status in primary and recurrent or metastatic breast cancer have confirmed the findingsnof historical retrospective studies which demonstrate that for biomarkers which influence routine clinical practice, EstrogennReceptor (ER), Progesterone Receptor (PR) and Human Epidermal growth factor Receptor type 2 (HER2), biopsy of recurrentnor metastatic disease is essential not only to confirm the presence of malignancy but to guide targeted medical therapy.nHistorically, discordance rates for the expression of receptors between primary and metastatic tumors, though variable, maynhave led to suboptimal treatment for a significant proportion of patients. While changes in PR are most common, changes innER (positive to negative or less frequently negative to positive) and the less common changes in HER2 (usually gain of HER2namplification) influence subsequent therapy for 1 in 6 patients and may thus impact upon survival. Recognition of the potentialnfor heterogeneity within the primary, between metastatic sites and over time requires further prospective study in breast cancernwhere the comparability of metastases from multiple sites and the need to biopsy successive recurrences have been less wellndocumented.nRecent prospective studies confirm the retrospective evidence that optimal patient care requires appropriate biopsy and pathologicalnassessment of recurrent or metastatic breast cancer.