Receptor discordance and phenotype change in metastatic breast cancer.

Abstract Background changes may occur in tumor phenotype and receptor status during the progression of breast cancer. Discordance between primary and metastases has implications for further treatment and prognosis. Methods 185 patients confirmed breast cancer metastasis were retrospectively analyzed during 1999–2019. All the pathological assessments of receptors and phenotypes of both primaries and metastases were recorded. Results rates of receptor discordance were 18.65%, 30.57%, and 16.06% for ER, PR, and HER2, respectively and 31.62% for phenotype change. Patients with ER discordance experienced a worse OS and PMS, and those with ER loss had worse PMS compared with ER positive concordance. Patients with PR discordance experienced poorer OS and loss of PR positivity also had decreased OS and PMS when comparing with PR positive concordance. There was also significantly poorer PMS of hormon receptor (HR) discordance than HR positive concordance. In phenotype change, the luminal A type concordance group showed better PMS result. Conclusions this study demonstrated that discordance in subtype and receptor status between primary and metastatic lesions ultimately affects the survival and has a potential impact on treatment options.