Breast cancer liver metastases and the impact of receptor expression on survival

The aim was to determine the frequency of altered receptor expression between primary breast cancer and liver metastases, and to examine the impact of receptor expression on survival. The conversion frequency of estrogen- (ER), progesterone- (PgR) and human epidermal growth factor receptor 2 (HER2) was investigated. The prognostic value of the receptor status in the primary tumor versus the metastases was estimated. Data on a population-based regional cohort of 7292 breast cancer patients from 2009 to 2018 were collected from the National Breast Cancer Register. Biomarker expression and intrinsic subtype was studied among those who developed liver metastases with available histopathological records. The study included 311 patients with liver metastases. Conversion of ER, PgR and HER2 occurred in 16%, 47% and 12% of patients, respectively. The subtype converted in 26%. HER2 amplification in the primary tumor or metastases was associated with improved survival. Positive ER and PgR in breast cancer and positive ER in liver metastases were beneficial for survival. A combined primary tumor and metastasis receptor evaluation had the highest prognostic value. Receptor conversion from primary tumor to liver metastases is common. HER2 amplification and positive ER or PgR are associated with improved survival. Accordingly, luminal HER2 positive tumors have improved survival compared to other intrinsic subtypes. To personalize treatment for each patient, a liver biopsy is warranted at diagnosis of breast cancer liver metastases.