Colon and Rectum Cancer : Screening, Symptoms, Diagnosis, Staging

by National Cancer Institute

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Screening

Screening for cancer before a person has symptoms can help the doctor find polyps or cancer early. Finding and removing polyps may prevent colorectal cancer. Also, treatment for colorectal cancer is more likely to be effective when the disease is found early.

To find polyps or early colorectal cancer:

• People in their 50s and older should be screened.
• People who are at higher-than-average risk of colorectal cancer should talk with their doctor about whether to have screening tests before age 50, what tests to have, the benefits and risks of each test, and how often to schedule appointments.

The following screening tests are used to detect polyps, cancer, or other abnormalities in the colon and rectum. The doctor can explain more about each test:

Fecal occult blood test (FOBT): Sometimes cancers or polyps bleed, and the FOBT can detect tiny amounts of blood in the stool. If this test detects blood, other tests are needed to find the source of the blood. Benign conditions (such as hemorrhoids) also can cause blood in the stool.

Sigmoidoscopy: The doctor checks inside the rectum and lower (sigmoid) colon with a lighted tube called a sigmoidoscope. If polyps are found, the doctor removes them. The procedure to remove polyps is called a polypectomy.

Colonoscopy: The doctor examines inside the rectum and entire colon using a long, lighted tube called a colonoscope. The doctor removes polyps that may be found.

Double-contrast barium enema (DCBE): A DCBE is a series of x-rays of the colon and rectum. The patient is given an enema with a barium solution, and air is pumped into the rectum. The barium and air outline the colon and rectum on the x-rays. Polyps may show up on the x-ray.

Digital rectal exam (DRE): A rectal exam is often part of a routine physical examination. The doctor or nurse inserts a lubricated, gloved finger into the rectum to feel for abnormal areas in the lower part of the rectum.

Symptoms

Common symptoms of colorectal cancer include:

• A change in bowel habits
• Diarrhea, constipation, or feeling that the bowel does not empty completely
• Blood (either bright red or very dark) in the stool
• Stools that are narrower than usual
• General abdominal discomfort (frequent gas pains, bloating, fullness, and/or cramps)
• Weight loss with no known reason
• Constant tiredness
• Nausea and vomiting

Most often, these symptoms are not due to cancer. Other health problems can cause the same symptoms. Anyone with these symptoms should see a doctor so that any problem can be diagnosed and treated as early as possible.

Usually, early cancer does not cause pain. It is important not to wait to feel pain before seeing a doctor.

Diagnosis

If a person has any signs or symptoms of colorectal cancer, the doctor must determine whether they are due to cancer or some other cause. The doctor asks about personal and family medical history and may do a physical exam.

If the physical exam and test results do not suggest cancer, the doctor may decide that no further tests are needed and no treatment is necessary. However, the doctor may recommend a schedule for checkups.

If tests show an abnormal area (such as a polyp), a biopsy to check for cancer cells may be necessary. Often, the abnormal tissue can be removed during colonoscopy or sigmoidoscopy. A pathologist checks the tissue for cancer cells using a microscope.

People may want to ask the doctor these questions before having a biopsy:

• How will the biopsy be done?
• Will I have to go to the hospital for the biopsy?
• How long will it take? Will I be awake? Will it hurt?
• Are there any risks? What are the chances of infection or bleeding after the biopsy?
• How long will it take me to recover? When can I resume a normal diet?
• How soon will I know the results?
• If I do have cancer, who will talk to me about the next steps? When?

Staging

If the biopsy shows that cancer is present, the doctor needs to know the extent (stage) of the disease to plan the best treatment. The stage is based on whether the tumor has invaded nearby tissues, whether the cancer has spread and, if so, to what parts of the body. Staging may involve some of the following tests and procedures:

Blood tests: The doctor checks for carcinoembryonic antigen (CEA) and other substances in the blood. Some people who have colorectal cancer or other conditions have a high CEA level.

Colonoscopy: If colonoscopy was not performed for diagnosis, the doctor examines the entire length of the colon and rectum with a colonoscope to check for other abnormal areas.

Endorectal ultrasound: An ultrasound probe is inserted into the rectum. The probe sends out sound waves that people cannot hear. The waves bounce off the rectum and nearby tissues, and a computer uses the echoes to create a picture. The picture shows how deep a rectal tumor has grown or whether the cancer has spread to lymph nodes or other nearby tissues.

Chest x-ray: X-rays of the chest can show whether cancer has spread to the lungs.

CT scan: An x-ray machine linked to a computer takes a series of detailed pictures of areas inside the body. The patient may receive an injection of dye. Tumors in the liver, lungs, or elsewhere in the body show up on the CT scan.

The doctor also may use other tests (such as MRI) to see whether the cancer has spread. Sometimes staging is not complete until the patient has surgery to remove the tumor.

Doctors describe colorectal cancer by the following stages:

Stage 0: The cancer is found only in the innermost lining of the colon or rectum. Carcinoma in situ is another name for Stage 0 colorectal cancer.

Stage I: The cancer has grown into the inner wall of the colon or rectum. The tumor has not reached the outer wall of the colon or extended outside the colon. Dukes' A is another name for Stage I colorectal cancer.

Stage II: The tumor extends more deeply into or through the wall of the colon or rectum. It may have invaded nearby tissue, but cancer cells have not spread to the lymph nodes. Dukes' B is another name for Stage II colorectal cancer.

Stage III: The cancer has spread to nearby lymph nodes, but not to other parts of the body. Dukes' C is another name for Stage III colorectal cancer.

Stage IV: The cancer has spread to other parts of the body, such as the liver or lungs. Dukes' D is another name for Stage IV colorectal cancer.

Recurrent cancer: This is cancer that has been treated and has returned after a period of time when the cancer could not be detected. The disease may return in the colon or rectum, or in another part of the body.

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