What is rectal cancer?

Rectal cancer occurs when cells that are not normal grow in your rectum. These cells often form in small growths called polyps. Not all rectal polyps turn into cancer. But most rectal cancer starts in a polyp.

Rectal cancer occurs most often in people older than 50.

What happens when you have rectal cancer?

Rectal cancer usually grows very slowly. It usually takes years for the cancer to become large enough to cause symptoms. If the cancer is not removed and keeps growing, it eventually will invade and destroy nearby tissues and then spread farther, first to nearby lymph nodes. From there it may spread to other parts of the body.

What are the symptoms?

Rectal cancer in its early stages usually doesn't cause any symptoms. Symptoms occur later, when the cancer may be harder to treat. The most common symptoms include:

• Blood in your stool or very dark stools.
• A change in your bowel habits, such as more frequent stools or a feeling that your bowels are not emptying completely.
• Pain in the belly or rectal pain.
• Low energy.

How can you prevent rectal cancer?

Screening tests can find or prevent many cases of rectal cancer. They look for a certain disease or condition before any symptoms appear.

Screening tests that may find rectal cancer early include:

• Stool tests, such as the fecal immunochemical test (FIT).
• Flexible sigmoidoscopy, which lets your doctor look at the inside of the lower part of your colon using a lighted tube.
• Colonoscopy, which lets your doctor look at the inside of your entire colon.

Experts say that most adults should start regular screening at age 50 and stop at age 74. Talk with your doctor about your risk and when to start and stop screening.

Here are other things you can do to help prevent rectal cancer:

• Watch your weight. Being very overweight may increase your chance of getting rectal cancer.
• Eat well. Eat more whole grains, fruits, vegetables, poultry, and fish. And eat less red meat, refined grains, and sweets.
• Limit drinking. Drink no more than 2 alcohol drinks a day if you're a man, and no more than 1 drink a day if you're a woman.
• Get active. Keep up a physically active lifestyle.
• Do not smoke. Smoking can make rectal cancer more likely. If you need help quitting, talk to your doctor about stop-smoking programs and medicines. These can increase your chances of quitting for good.

How is rectal cancer treated?