Colon cancer is treated with chemotherapy, which refers to the treatment with chemical drugs, usually anti-tumor drugs, such as capecitabine and tigeo for oral use, and oxaliplatin, irinotecan and even paclitaxel for intravenous use. Radiotherapy refers to the treatment with radiation and is used more often for low and medium rectum, because the impact of radiotherapy is relatively high and all organs within the radiotherapy irradiated area may be affected. As the colon is inside the human abdominal cavity, it is not used for radiotherapy because radiotherapy can cause effects on organs inside the abdominal cavity, most commonly the small intestine which may lead to radiation enteritis, intestinal obstruction, intestinal fistula, etc.