Minimally Invasive Conversion Surgery for Unresectable Gastric Cancer with Splenic Metastasis and Splenic Vein Tumor Thrombus: A Case Report.

While the importance of conversion surgery has increased with the development of systemic chemotherapy for gastric cancer (GC), reports of conversion surgery for patients with GC with distant metastasis and tumor thrombus are extremely scarce, and a definitive surgical strategy has yet to be established. Herein, we report a 67-year-old man with left abdominal pain referred to our hospital following a diagnosis of unresectable GC. Esophagogastroduodenoscopy and contrast-enhanced abdominal computed tomography (CT) revealed advanced GC with splenic metastasis. A splenic vein tumor thrombus (SVTT) and a continuous thrombus to the main trunk of the portal vein were detected. The patient was treated with anticoagulation therapy and systemic chemotherapy comprising S-1 and oxaliplatin. One year following chemotherapy initiation, a CT scan revealed progressive disease (PD); therefore, the chemotherapy regimen was switched to ramucirumab with paclitaxel. After 10 courses of chemotherapy resulting in primary tumor and SVTT shrinkage, the patient underwent laparoscopic total gastrectomy (LTG) and distal pancreaticosplenectomy (DPS). He was discharged without complications and remained alive 6 months postoperatively without recurrence. In summary, the wait-and-see approach was effective in a patient with GC with splenic metastasis and SVTT, ultimately leading to an R0 resection performed via LTG and DPS.