IntroductionEvery year, approximately 225,000 women are diagnosed with breast cancer and another 40,000 die from the disease in the US. About 75% of all metastases will occur within the first 5 years after diagnosis of early-stage disease. This has been found to be especially true for hormone receptor-negative disease. Unfortunately, metastases can occur beyond that time, sometimes up to 30 years later, which is more common in hormone-positive disease [1,2]. Breast cancer will typically metastasize to lymph nodes, bone, lungs, liver, and brain. Most commonly, metastatic spread of any cancer type to the gastrointestinal tract is considered an uncommon phenomenon. One study of approximately 2500 cases, found only 21 patients (<1%) with metastasis to the gastrointestinal tract [3]. Of secondary tumors to the gastrointestinal tract, breast is second only to melanoma [4]. In one study that looked specifically at the colon and rectum, the leading source of metastases was breast, with melanoma second [5]. In an autopsy study performed on 707 cases of metastatic breast cancer, the stomach was involved in 10% of cases, small intestine in 9%, and large intestine in 8%, with the peritoneum involved in 25% of cases. Overall, the gastrointestinal tract was involved in 16% of cases [6] A non-autopsy study done in 2005 at The Mayo Clinic showed that of 12,000 diagnosed with metastatic disease secondary to breast cancer, 73 (0.6%) were found in either the GI tract or peritoneum: esophagus (8%), stomach (28%), small intestine (19%), and colon and rectum (45%) [7].Histological studies have found that lobular carcinoma metastasized to the same metastatic sites as ductal carcinoma; however lobular carcinoma frequently metastasized to unusual sites like the gastrointestinal tract, peritoneum, and adnexa [8][9][10][11][12]. In one of the earliest papers on the subject, all of the metastases to the stomach were infiltrating lobular cancer, and other papers had between 75-97% lobular histotype [13][14][15][16]
AbstractBackground: Those diagnosed with breast cancer are surviving longer due to advances in treatment. Metastatic spread to any site may not occur for years after primary surgical and systemic treatments and will most likely be diagnosed by General Practitioners. Breast cancer rarely metastasizes to the gastrointestinal tract. Due to this, scarce literature is available; mostly case-reports or small caseseries. Our aim is to review two recent cases and to highlight our institution's data. General Practitioners need to remember the potential gastrointestinal metastatic spread of breast cancer.
