A 67-year-old man was admitted with melena. A colonoscopy detected advanced rectal cancer, and a CT scan revealed invasion of the seminal vesicle and prostate. Given the wild-type RAS status of the tumor, we administered 6 courses of XELOX plus cetuximab as neoadjuvant chemotherapy. After treatment, the tumor had shrunk, and the rectum had narrowed. Later, following a diagnosis of coronary artery disease, colostomy was performed. The patient was treated for the coronary artery disease for 2 months. Following treatment, tumor progression was detected, and hence, the patient was treated with the same chemotherapy regimen for 4 more courses. We performed a laparoscopic assisted abdominoperineal resection of the rectum with combined resection of the seminal vesicle and prostate. Pathological examination revealed a complete response to treatment. Six months after the operation, no recurrence was observed without further adjuvant chemotherapy.