[Robot-Assisted Resection for Ascending Colon Cancer with a Tumor Thrombus in the Superior Mesenteric Vein after Neoadjuvant Chemotherapy-A Case of Report].

An 81-year-old woman visited our hospital for severe anemia and was diagnosed with ascending colon cancer with a tumor thrombus in the superior mesenteric vein(SMV). After 8 courses of mFOLFOX6+bevacizumab therapy followed by 7 courses of fluorouracil and leucovorin+bevacizumab therapy, the primary lesion and tumor thrombus were found to be shrinkage. Then we performed robot-assisted right hemicolectomy and resection of SMV involving the tumor thrombus. The patient was discharged on postoperative day 19. Histological findings revealed residual tumor thrombus in the SMV. The patient is currently under observation at 4 months postoperatively without adjuvant chemotherapy.