Long-term response on letrozole for gastric cancer: A case report

RATIONALE: Hormone therapies, particularly those targeting estrogen and its receptors, are a key treatment modality for patients with estrogen receptor (ER)-positive breast or ovarian cancer. Some gastric cancers (GCs) express ERs, and preclinical studies suggest the potential of estrogen-targeting hormone therapy on GC; however, the clinical relevance of this hormone therapy on GC treatment has not been well elucidated. PATIENT CONCERNS: An 80-year-old female was admitted to our department with hypogastric pain and vomiting. Computed tomography demonstrated small bowel obstruction, and laparotomy after bowel decompression revealed peritoneal dissemination consisting of a poorly-differentiated adenocarcinoma. Intestinal bypass between the ileum and transverse colon was performed. DIAGNOSES: The tumor was ER- and mammaglobin-positive, indicating that it originated from a breast cancer. Diagnostic imaging revealed no evidence of breast cancer; however, right axillary ER- and mammaglobin-positive lymphadenopathy was found. INTERVENTIONS: The patient received hormone therapy using letrozole based on a clinical diagnosis of occult breast cancer with peritoneal dissemination and right axillary lymph node metastasis. OUTCOMES: The patient remained disease free until 37 months but deceased at 53 months from the onset of disease. An autopsy revealed no tumor cells in the right breast tissue; however, there was a massive invasion of cancer cells in the stomach. LESSONS: A patient with ER positive GC with peritoneal dissemination and right axillary lymph node metastasis presented remarkable response to letrozole. The long-term survival obtained using letrozole for a patient with GC with distant metastasis suggests the potential of estrogen targeting hormone therapies for GC.