Colon and Rectal Cancer

The colon and rectum are parts of the digestive system. They form a long, muscular tube called the large intestine. The colon is the first 4 to 5 feet of the large intestine, and the rectum is the last several inches.

Partly digested food enters the colon from the small intestine. The colon removes water and nutrients from the food and turns the rest into waste. The waste passes from the colon into the rectum and then out of the body through the anus.

The colon cancer is the cancer that forms in the tissues of the colon (the longest part of the large intestine). Most colon cancers are adenocarcinomas (cancers that begin in cells that make and release mucus and other fluids).

The rectal cancer is the cancer that forms in the tissues of the rectum.

When colorectal cancer spreads outside the colon or rectum, cancer cells are often found in nearby lymph nodes. If cancer cells have reached these nodes, they may also have spread to other lymph nodes or other organs.

Risk Factors

It is clear that colorectal cancer is not contagious.

Colorectal cancer is more likely to occur as people get older. Usually, people with this disease are diagnosed after age 50.

Polyps are growths on the inner wall of the colon or rectum. They are common in people over age 50. Most polyps are benign (not cancer), but some polyps can become cancer. Finding and removing polyps may reduce the risk of colorectal cancer.

Close relatives (parents, brothers, sisters, or children) of a person with a history of colorectal cancer are somewhat more likely to develop this disease themselves, especially if the relative had the cancer at a young age. If many close relatives have a history of colorectal cancer, the risk is even greater.

Changes in certain genes increase the risk of colorectal cancer.

A person who has already had colorectal cancer may develop colorectal cancer a second time. Also, women with a history of cancer of the ovary, uterus (endometrium), or breast are at a somewhat higher risk of developing colorectal cancer.

A person who has had an inflammation of the colon (such as Crohn's disease) for many years is at increased risk of developing colorectal cancer.

Studies suggest that diets high in fat (especially animal fat) and low in calcium and fiber may increase the risk of colorectal cancer. Also, some studies suggest that people who eat a diet very low in fruits and vegetables may have a higher risk of colorectal cancer.

A person who smokes cigarettes may be at increased risk of developing polyps and colorectal cancer.

Because people who have colorectal cancer may develop colorectal cancer a second time, it is important to have checkups

Symptoms

   Common symptoms in colorectal cancer include:

-             diarrhea or constipation

-             Feeling that your bowel does not empty completely

-             blood (either bright red or very dark) in your stool

-             Frequently having cramps

-             Losing weight with no known reason

-             Feeling very tired all the time

-             Having nausea

Usually, early cancer does not cause pain.