Complete remission from peritoneal metastasis of late recurrent breast cancer by endocrine therapy: a case report

BACKGROUND: Peritoneal dissemination associated with the postoperative recurrence of breast cancer is relatively low (3–6%). Although the prognosis of patients with peritoneal metastasis is generally short (7–26 months), we experienced a unique case in which complete remission was achieved for more than 6 years with endocrine therapy alone. CASE PRESENTATION: An 81-year-old woman presented an upper abdominal tumor and loss of appetite. Computer tomography (CT) scan revealed a tumor in the duodenum and the head of pancreas, which malignant lymphoma was suspected. The exploratory laparotomy demonstrated a tumor located in the greater curvature of the pylorus to the transverse colon, and peritoneal dissemination. Because of the previous history of breast cancer 11 years ago and the immunopathological findings, recurrence of breast cancer was diagnosed. Lung metastasis was also detected postoperatively and the endocrine therapy using letrozole was introduced. After a year, CT scan confirmed complete remission from the metastasis. Two years later, tumor markers fell within the normal limit. CONCLUSIONS: A rare case of late-phase metachronous peritoneal metastasis of the breast cancer where complete remission was obtained by a single endocrine agent was presented.