Colorectal cancer is the third-most common form of cancer. About 1.8 million people were diagnosed with the disease worldwide in 2018. When it occurs in the rectum, surgery is difficult and requires highly advanced skills as it is close to many organs and surrounded by important blood vessels and nerves. When it is near the anus, many surgeons remove the anus, leaving the patient with a permanent stoma. But a Japanese doctor has succeeded in preserving the anus in over 90% of cases.