[A case of early gastric cancer with multiple synchronous bone metastases treated complete response with S-1+CDDP]

We report a case of complete response (CR) following induction chemotherapy using S-1 for a patient with early gastric cancer accompanied by multiple synchronous bone metastases. An asymptomatic 70-year-old woman was diagnosed with early gastric cancer by upper gastrointestinal endoscopy during a periodic medical examination. An abdomino-pelvic computed tomography (CT) scan revealed no primary tumor in the stomach and the absence of lymph node or liver metastases. However, osteoplastic changes were detected in the lumbar vertebrae and the ilium. Multiple synchronous bone metastases from early gastric cancer were detected on magnetic resonance imaging, bone scintigraphy, and positron emission tomography- CT. After a regimen consisting of 15 courses of S-1 plus cisplatin (CDDP), and an additional 5 courses of S-1 were administered, clinical CR was confirmed for the bone metastases. Laparoscopic distal gastrectomy with D1 lymphadenectomy was performed for treating the primary gastric cancer 33 months after the initiation of chemotherapy. Pathological CR was also achieved for the primary gastric cancer. Imaging analysis did not show disease progression 48 months after the initiation of chemotherapy. Synchronous bone metastases from early gastric cancer are extremely rare, and a good outcome was achieved in the present case through induction chemotherapy.