Clinical features and prognosis of breast cancer with gastric metastasis.

Breast cancer rarely metastasizes to the gastrointestinal tract, including the stomach. Due to the rarity of this metastasis, it is occasionally confused with a primary stomach malignancy. However, discriminating characteristic features with clinical implications may exist. The aim of the current study was to analyze the clinical features and prognosis of breast cancer with gastric metastasis. Between January 1994 and October 2016, 13 patients at Samsung Medical Center (Seoul, Korea) were clinically or pathologically determined to have breast cancer with gastric metastasis. The present study retrospectively collected clinicopathological data from the electronic medical records of these 13 female patients. At breast cancer diagnosis, the median patient age was 45 years. A total of 7 patients (53.8%) presented with invasive lobular carcinoma (ILC) and 6 (46.2%) with invasive ductal carcinoma. Of the 13 patients, 11 were stage I-III at initial breast cancer diagnosis and underwent surgery. Positivity of breast cancer tissue samples for estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) was 92.3, 76.9 and 0%, respectively. Positivity of gastric metastasis lesions, based on immunohistochemistry results, was 81.8, 50 and 0% for ER, PR and HER2, respectively. The stomach was the location of the first metastatic lesion in 6 out of the 11 patients (54.5%) with de novo stage I-III cancer. The median time interval from initial breast cancer diagnosis to stomach metastasis was 77.5 months. The 3-year survival rate was 79.1%, and the estimated mean survival time was 35.1 months. Breast cancer with gastric metastasis is rare, and due to this fact, a thorough pathological review and greater clinical suspicion are required in these cases.