A new study has described breast cancer metastasis to the stomach, a rare type of remote recurrence. The study included eight women with breast cancer metastasis to the stomach diagnosed between 1995 and 2008. All of the breast tumors were estrogen receptor positive (ER+), two were HER2 overexpressing, and most were lobular carcinoma. The median interval between the primary breast cancer and the gastric involvement was 41 months, although the range was wide (range 2 to 82 months). All of the patients received chemotherapy and two of them were also administered hormonal treatments. Two patients underwent surgical intervention for palliation. An additional patient who had the stomach as the only metastatic site will proceed to surgical resection of the stomach. These three patients were still alive after 9, 39 and 44 months of follow-up, respectively.

The chemotherapy response rate was 50% (one complete response, three partial responses), and the median survival time was 11 months (range 1 month to greater than 44 months). The authors conclude that breast cancer metastasis to the stomach can be distinguished from primary gastric cancer by comparing biopsies from the gastric metastasis with the histological slides from the original breast tumor. The preferred treatment for gastric metastasis to the stomach is the appropriate systemic treatment for metastatic breast cancer. Surgery might be effective in cases where the gastric metastasis is the only evident remote recurrence or to relieve pain or other symptoms.

Previous studies have also reported lobular-gastric metastasis connection

Previous studies have also reported that gastric metastasis from breast cancer are almost always from lobular primary tumors. Symptoms typically include gastric discomfort and weight loss. Like lobular breast tumors, lobular gastric metastasis can be difficult to detect radiologically and are not necessarily visible endoscopically because they may cause only a thickening of the gastric wall. Therefore, it is vital that biopsies be performed and compared to the original tumor if gastric metastasis is suspected.