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

Abstract

IntroductionRecent 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 MethodsWe 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. ResultsThe 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. ConclusionDiscordance 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.