[A Case of Pathological Complete Response of Colon Cancer after Systemic Chemotherapy with mFOLFOX6]

Neoadjuvant chemoradiotherapy is a standard mode of therapy for rectal cancer but not colon cancer. A 74-year-old man undergoing treatment for prostate cancer was found to have a tumor in both the sigmoid colon and liver. Colonoscopy showed a type 2 tumor of the sigmoid colon, with a biopsy confirming a diagnosis of well differentiated tubular adenocarcinoma. Computed tomography demonstrated a tumor of the sigmoid colon with metastasis to the liver. As there was a high suspicion of invasion of the left ureter, we decided to administer mFOLFOX6 as neoadjuvant chemotherapy prior to tumor resection. After 8 courses of mFOLFOX6, both the primary lesion and liver metastasis significantly decreased in size. Subsequently, the patient underwent a sigmoidectomy and partial hepatectomy. Histopathological examination revealed pathological complete response(Grade 3). It is important to reveal effective cases of neoadjuvant chemotherapy, the appropriate treatment regime and timing of surgical intervention so as to advance therapeutic strategies for the treatment of colon cancer.