What is rectal cancer?

Rectal cancer occurs when abnormal cells grow out of control in your rectum.

If the tumor was small and had not spread, your doctor may have removed it during the colonoscopy. But you may need surgery to remove the cancer if the tumor was too big or had spread too far to be removed during a colonoscopy. If cancer has spread to another part of your body, such as the liver, you may need surgery or other treatments.

Treatment for rectal cancer may also include radiation therapy. Medicines that destroy cancer cells, such as chemotherapy or targeted therapy, may be used. And medicines that work with your body's immune system, called immunotherapy, may also be used.

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.

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.

Surgery is almost always used to treat rectal cancer. The cancer is more easily removed when it is found early. If the cancer has spread beyond the rectum, you may also need radiation or chemotherapy. Other medicines that destroy cancer cells, such as targeted therapy or immunotherapy, may also be used.

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 occult blood test.
• 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 using a thin, flexible tube.

Experts recommend starting screening at age 45 for people who are at average risk. 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.
• If you drink alcohol, limit how much you drink. Any amount of alcohol may increase your risk for some types of cancer.
• 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.

If your doctor thinks you may have rectal cancer, you'll be asked about your past health and have a physical exam. Your doctor may use a lighted scope to view the inside of your colon (colonoscopy) and take a biopsy. You may also have blood or stool tests and a CT scan.

Taking medicines as prescribed and getting enough sleep may help you feel better. Try to eat foods with protein and extra calories. Try to be active each day if you can. Talk to your doctor if pain keeps you from your daily activities. Consider joining a support group or talking with a counselor.

The type of surgery depends on the size and location of the cancer. The goal is to remove all the cancer and a border of normal tissue (margin) around it.

• Small areas of cancer in the lining of the rectum may be removed through the anus.
• Larger areas of cancer may be removed through one incision in the belly (open surgery). Or several small incisions may be used (minimally invasive surgery). The doctor takes out the part of the rectum that contains cancer. Nearby lymph nodes are also removed and checked for cancer. In some cases, the doctor may also need to remove the lower colon and the anus.

A colostomy may be needed for a while to let the rectum heal after surgery. In some people, the colostomy will be permanent. If you need a colostomy, you will get help from a nurse who specializes in ostomy care.

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.