S3700 Role of Immunotherapy in the Treatment of Recurrent Hereditary Diffuse Gastric Cancer

Abstract

Metastasis to the stomach is very rare in the case of breast cancer (BC). The incidence rate of gastric metastasis (GM) is estimated to be about 0.3%. In general, the most common areas of BC metastasis are bone, liver, and lung. Retrospective studies have found that the majority of GM is derived from lobular breast cancer compared with other breast cancer subtypes and higher percentages are hormone positive. Previous studies suggest varying intervals between diagnosis of primary breast cancer and the detection of GM anywhere from 5 to 20 years. Unfortunately, published data is limited to single case reports or small series. Case Description/Methods: Patient is a 73 year old female past medical history of breast cancer initially diagnosed 13 years prior with stage IIB invasive right breast lobular carcinoma ER/PR positive, HER2 negative. Patient received right mastectomy and completed chemotherapy and radiation without evidence of metastasis. Subsequent imaging including PET scans revealed no evidence of disease. 10 years later biopsy of left breast showed moderately differentiated invasive carcinoma ER/PR positive, HER2 negative. Patient underwent mastectomy with node sampling that was negative for involvement. Patient was continued on chemotherapy. PET scan and brain MRI done 3 months prior to EGD showed no evidence of disease. Patient presented to our outpatient GI clinic with complaints of dysphagia. She had an episode of suspected food impaction relieved by vomiting. Patient was experiencing epigastric discomfort including occasional globus sensation for several months prior to the incident. EGD showed erythematous gastric mucosa with nodularity no obvious mass was found. Biopsies revealed ER/PR positive, HER2 negative, metastatic adenocarcinoma in gastric body and antrum. Patient decided not to pursue aggressive measures in regards to metastasis. She was started on PPI twice daily which helped alleviate epigastric symptoms. Repeat EGD showed improvement of gastritis (Figure 1). Discussion: Reports on GM from breast cancer are limited do to the rarity. In reviewing previous studies there is a similar theme. GM presents without other signs of metastasis. Our patient had multiple negative scans falsely suggesting no metastasis. Although infrequent, physicians should still consider the possibility of GM in patients with breast cancer and non specific GERD symptoms. More so in patients with history of lobular carcinoma and hormone positive subtypes.[3699] Figure 1. Endoscopic imaging of gastric metastasis.