C18: Malignant neoplasm of colon

Malignant neoplasm of the colon, or colon cancer, is a type of cancer that occurs in the colon, or large intestine. This group of conditions typically starts as small, noncancerous clumps of cells called polyps that over time can develop into colon cancers. Even though colon cancer typically affects older adults, it can happen at any age. Symptoms may include changes in bowel habits, such as constipation or diarrhea, blood in stool, persistent abdominal discomfort, fatigue, and unexplained weight loss. As the disease progresses, it can spread to nearby lymph nodes and eventually to other parts of the body, which can affect multiple systems. The exact cause of most colon cancers is unclear, but certain factors can increase the risk of disease, including age, smoking, heavy alcohol use, a high-fat diet, and having certain inherited disorders. These cancers are not transmitted from person to person.