Colon and rectal cancer, known together as colorectal cancer, occurs when normal cells that line the colon or rectum grow out of control becoming cancerous. The rapidly growing cells can cause a mass of tissue, which may or may not be cancerous and may result in a tumor.
Colon cancer forms in the colon located at the lower part of the digestive system. Rectal cancer forms in rectum, which is the last few inches of the large intestine that ends at the anus.
The colon is a 6-foot long muscular tube that connects the rectum to the small intestine. Together, the colon and rectum are called the large intestine. The large intestine processes the body’s waste by removing water from it and storing stool. Once the colon is ready to be emptied, the stool is deposited into the rectum to be eliminated.
According to the American Academy of Family Physicians, 70 to 90 percent of colon and rectal cancers start as polyps, abnormal tissue growths on the inner surface of the colon or rectum.
Most polyps are benign. Small polyps can take up to 10 years to develop into cancer and can be prevented with regular cancer screenings and removal.
The two most common types of polyps found in the colon and rectum are:
As a general rule, the larger the polyp, the greater the chances of it developing into cancer. Oncologists remove most large polyps, whether cancerous or not, to prevent them from developing into a cancer.
The NCI says colorectal cancer is the fourth leading cause of cancer deaths among men and women in the U.S. Age is by far the greatest factor in who might get colorectal cancer and who might die from it.
Patients can’t control some risk factors, such as genetic conditions, but they can reduce some risk factors through their own actions. Doing such things as adjusting diet and stopping tobacco use help prevent colon and rectal cancer.
While anyone can get colon or rectal cancer, those with the following factors are at a higher risk:
In many cases, colon or rectal cancer may not present any symptoms. When symptoms are present they may include:
Colon and rectal cancers have a high cure rate if caught early. People younger than age 40 rarely get colorectal cancer. People with normal risk for colorectal cancer should begin screening around age 50. People with a high risk, such as those with family history or type 2 diabetes and colorectal cancers, should begin cancer screenings at age 45.
Colorectal cancer screenings may include the following:
More detailed information about colorectal cancer screening and diagnosis is available.
If a polyp or tumor is found during screening, the doctor will remove the growth and send it to a laboratory for analysis. If the growth is confirmed as cancer, a number of treatments are available, including:
Treatment of colorectal cancer will vary depending on the size, location and stage of the growth.