[A Case of Synchronous Liver Metastasis of Ascending Colon Cancer with Pathological Complete Response to S-1/Oxaliplatin (SOX) and Bevacizumab].

A 77-year-old man was diagnosed with ascending colon cancer with synchronous liver metastasis. Per our policy we first only performed a right hemicolectomy (pSSN2H2M0, stage IV). We then planned S-1 and oxaliplatin (SOX) plus bevacizumab (Bmab) chemotherapy as a neoadjuvant for the resection of liver metastasis. After 4 courses, enhanced CT and EOB-MRI findings showed the liver tumor had significantly decreased in size with no side effects, and we performed a partial liver resection for the S7 lesion. Postoperatively, histopathological analysis revealed only a fibrotic lesion and no cancerous cells in the resected specimen, indicating that chemotherapy had downgraded the tumor to Grade 3. Adjuvant chemotherapy was not continued owing to the patient's refusal, but no recurrence was noted 18 months after the second operation. SOX plus Bmab chemotherapy is, therefore, effective in terms of its anti-tumor effects, tolerance, and accessibility. We believe SOX plus Bmab chemotherapy can be considered as an effective option for cases with synchronous liver metastasis of colon cancer as neoadjuvant chemotherapy for interval liver resection.