Colorectal cancer

[Gregory]

Family history and some dietary factors (low fiber, high fat) increase a person’s risk of colorectal cancer.
Typical symptoms include bleeding during a bowel movement, fatigue, and weakness.
Screening tests are important for people over 50.
Colonoscopy is often used to make the diagnosis.
Cancer that is caught early is most curable.
Surgery is usually done to remove the cancer.

Almost all cancers of the large intestine and rectum (colorectal) are adenocarcinomas, which develop from the lining of the large intestine (colon) and rectum. Colorectal cancer usually begins as a buttonlike growth on the surface of the intestinal or rectal lining called a polyp. As the cancer grows, it begins to invade the wall of the intestine or rectum. Nearby lymph nodes also may be invaded. Because blood from the wall of the intestine and much of the rectum is carried to the liver, colorectal cancer can spread (metastasize) to the liver after spreading to nearby lymph nodes.
In Western countries, cancer of the large intestine and rectum is one of the most common types of cancer and the second leading cause of cancer death. The incidence of colorectal cancer begins to rise sharply around age 40 to 50. Each year, about 140,250 people in the United States develop colorectal cancer and about 50,630 die.
Colorectal cancer is slightly more common among men than women. About 5% of people with colon cancer or rectal cancer have cancer in two or more sites in the colon and rectum that do not seem to simply have spread from one site to another.