A 6 6-year-old woman with hematochezia was admitted to our hospital. A colonoscopy detected KRAS wild-type rectal cancer. An abdominal computed tomography (CT) scan revealed a liver metastasis, and invasion to the uterus was suspected. The patient underwent a laparotomy, and intraoperative cytology and peritoneal dissemination proved positive. The tumor had invaded the uterus. We administered chemotherapy consisting of 5-fluorouracil, Leucovorin, and oxaliplatin(mFOL FOX6)plus panitumumab. A CT scan and colonoscopy performed after 10 courses of chemotherapy indicated remarkable tumor regression. An abdominal CT scan did not detect any liver metastases, and we performed a laparoscopic low anterior resection. In the second operation, peritoneal dissemination and washing cytology were negative. The pathological diagnosis of the surgically resected specimen was ypStageII. The patient is recurrence-free 7 months after surgery.