Prognostic Impact of Discordance in Hormone Receptor Status Between Primary and Recurrent Sites in Patients With Recurrent Breast Cancer

Abstract

Introduction: Recent retrospective studies have reported discordance rate of hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) statuses between primary and recurrent tumors and prognostic values of discordance. However, the results of these reports may possibly include analytical error.

Patients and methods: We analyzed 153 patients from whom pathological specimens of tumor tissues were available from both primary and recurrent sites. For all specimens, immunohistochemistry was performed for these statuses with a standardized method. Two experienced pathologists evaluated these specimens in a blinded fashion.

Results: The discordance rates for estrogen receptor, progesterone receptor, and HER2 were 18%, 26%, and 7%, respectively. Subtype changes based on HR and HER2 status occurred in 21% of patients. Clinical outcome was significantly worse in the patients with the tumors that were primarily HR-positive (HR(+)) converted to HR-negative (HR(-)) at recurrent sites than in the patients with the tumors in which HR status did not change or converted from HR(-) to HR(+) (P = .001). Clinical outcome was also significantly worse in the patients with the primarily HR(+) tumor that converted to triple negative in the recurrence sites than in the patients with a constantly HR(+) tumor (P < .001). By the Cox multivariate analyses, loss of HR expression and conversion to triple negative at the recurrence sites were independent indicators of worse clinical outcome.

Conclusion: Discordance in HR and HER2 status often occurred between primary and recurrent breast cancer and had independent prognostic impact in the patients with recurrent breast cancer.

Keywords: Discordance; HER2; HR; Overall survival; Prognostic factor.