Impact of Chemotherapy with S-1 and Oxaliplatin (SOX) in Combination with Molecular-targeting Agents on Colorectal Liver Metastases

AIM: The aim of this study was to evaluate the impact of chemotherapy with molecular-targeting agents on liver metastases from colorectal cancer. PATIENTS AND METHODS: Six patients with synchronous colorectal liver metastases who underwent hepatectomy after chemotherapy with S-1 and oxaliplatin (SOX) between January 2010 and December 2011 at the Department of Surgery, Kashiwa Hospital, the Jikei University School of Medicine were enrolled. Two patients received only SOX as chemotherapy, while the others received SOX in combination with one of the three molecular-targeting agents, bevacizumab, cetuximab, and panitumumab. RESULTS: In the two patients who received SOX alone, liver metastases completely disappeared at more than six months after starting chemotherapy as shown by computed tomographic (CT) scan. However, malignant cells were diffusely detected by pathological examination at the site of liver metastases, as detected by CT scan before chemotherapy. In the other four patients who received SOX in combination with molecular targets, the size of liver metastases appeared unchanged at three months after limited chemotherapy by CT scan. Pathologically, few malignant cells were detected, only at the borderline of the tumor, while most tumor cells inside the tumor were necrotized and been replaced by fibroconnective tissue. CONCLUSION: Molecular-targeting agents may induce tumor necrosis rapidly from inside the tumor, which might not be detected by CT scan before surgery.