Background: Breast cancer metastasis to the stomach is rare. It is very important to distinguish a breast cancer metastasis to the stomach from a primary gastric cancer on the basis of clinical, endoscopic, radiological and histopathological features, in order to administer the appropriate treatment.
Patients and methods: Eight patients with breast cancer metastasis to the stomach were identified in our database between 1995 and 2008. The clinicopathological data and outcome from the medical records of these patients were then reviewed.
Results: The median age at initial breast cancer diagnosis was 59.5 years (range 44-75 years), while the median interval between the primary breast cancer and the gastric involvement was 41 months (range 2-82 months). The primary breast cancer histological subtype was mostly lobular carcinoma. All the biopsy specimens were estrogen receptor (ER), cytokeratin (CK) 7 and gross cystic disease fluid protein-15 (GCDFP-15) positive and CK-20 negative, while two of them (25%) were HER-2-neu positive. All the patients received chemotherapy and two of them were also treated with hormonal treatment. Two patients underwent surgical intervention, while one patient who had gastric involvement as the only metastatic site will proceed to surgical resection of the stomach. All these three patients were alive after 9, 39 and 44 months of follow-up, respectively. The response rate to chemotherapy was 50% (1 complete response [CR], 3 partial responses [PR]), and the median survival was 11 months (range, 1-44+ months).
Conclusion: Breast cancer metastasis to the stomach can be differentiated from primary gastric cancer by comparing the biopsies from the gastric metastasis with the original histological slides from the primary breast tumor. Appropriate systemic treatment for metastatic breast carcinoma is the preferred treatment, whereas surgical intervention should be reserved for palliation or may be indicated in cases of solitary resectable gastrointestinal tract metastases.