Abstract
PURPOSE: We investigated the prognostic impact of discordance between the receptor status of primary breast cancers and corresponding metastases. METHODS: A total 144 patients with breast cancer and distant metastasis were investigated. The estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status of primary tumor and corresponding metastases were assessed. Tumor phenotype according to receptor status was classified as triple-negative phenotype (TNP) or non-TNP. Concordance and discordance was determined by whether there was a change in receptor status or phenotype between primary and metastatic lesions. RESULTS: The rates of discordance between primary breast cancer and metastatic lesions were 18.1%, 25.0%, and 10.3% for ER, PR, and HER2, respectively. The rates of concordant non-TNP, concordant TNP and discordant TNP were 65.9%, 20.9%, and 13.2%, respectively. Patients with concordant ER/PR-negative status had worse postrecurrence survival (PRS) than patients with concordant ER/PR-positive and discordant ER/PR status (p=0.001 and p=0.021, respectively). Patients who converted from HER2-positive to negative after distant metastasis had worst PRS (p=0.040). Multivariate analysis showed that concordant TNP was statistically significant factor for worse PRS (p<0.001). CONCLUSION: Discordance in receptor status and tumor phenotype between primary breast cancer and corresponding metastatic lesions was observed. Patients with concordant TNP had worse long-term outcomes than patients with concordant non-TNP and discordant TNP between primary and metastatic breast cancer. Identifying the receptor status of metastatic lesions may lead to improvements in patient management and survival.