Lobular Metastatic Breast Cancer Patients With Gastrointestinal Involvement: Features and Outcomes

Introduction: Metastatic breast cancer typically involves the lungs, bones, brain, and liver and only occasionally affects the gastrointestinal (GI) tract. The relevant published data have been limited to case reports and small series of patients. Patients and Methods: The present study focused on the treatment and outcomes of breast cancer patients with GI involvement diagnosed at the European Institute of Oncology. We analyzed the clinicopathologic features of the GI metastases and compared them with those of the primary tumors according to their histologic type (ductal or lobular carcinoma). Results: From the database of the Department of Pathology, 40 patients who had undergone endoscopy or GI surgery with a final diagnosis of metastatic breast cancer from 2000 to 2014 were identified. The greatest proportion of patients (75%) had had primary invasive lobular carcinoma. Of the 40 patients, 82% had hormone receptor-positive disease in the metastatic lesion; 34 patients were candidates for systemic therapy. The median length of observation after GI metastasis was 18 months (range, 0.6-79 months). The overall survival from the diagnosis of GI involvement was 33 months (95% confidence interval, 16.8-38.3 months). Conclusion: Lobular breast carcinoma has a greater propensity to metastasize to the GI tract compared with other breast cancer subtypes. In the presence of GI symptoms, even if nonspecific, the GI tract should be thoroughly studied. Systemic treatment, including hormonal therapy, should be considered.