[A Case of an Unresectable Locally Advanced Rectal Cancer with Surrounding Organ Invasion Successfully Resected after Chemotherapy with mFOLFOX6 plus Cetuximab].

ABSTRACT

A 63-year-old man visited our hospital with pain on micturition and was found to have a large rectal tumor with urinary bladder invasion on enhanced abdominal computed tomography (CT). The tumor appeared to be unresectable at presentation; thus, sigmoid colostomy was performed and chemotherapy was initiated. The tumor was found to be EGFR-positive and contained a wild-type KRAS. The mFOLFOX6 plus cetuximab (c-mab) regimen was initiated. The follow-up CT scan showed good tumor shrinkage after 4 courses of chemotherapy; 4 additional courses were administered. The tumor eventually regressed by more than 60% and was judged to be resectable. High anterior resection of the rectum with partial resection of the bladder was performed. Abdominal wall metastasis was detected 8 months after surgery, and additional resection was performed. The patient remained well with no other recurrence 8 months after the high anterior resection. Although chemoradiotherapy is the standard preoperative treatment of locally advanced rectal cancer, systemic therapy is effective in certain cases such as substantial tumor invasion of adjacent organs or metastasis. Here, we present a case of rectal cancer that became curatively resectable after preoperative chemotherapy with mFOLFOX6 plus c-mab.