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Overview

Colorectal cancer refers to cancer that starts in the colon or rectum. The colon is a six-foot muscular tube that connects the small intestine to the rectum. The rectum, the lower six inches of the digestive tract, holds stool before it leaves the body. These cancers occur when cells lining the colon or the rectum become abnormal and grow out of control. Colorectal cancer is the fourth most common type of cancer and the second most common cause of cancer death in the U.S.

Screening & Detection

Screening Procedures

Colonoscopy: The doctor uses a colonoscope (a flexible tube-like device equipped with a miniaturized camera) to view the entire colon and detect small polyps (precancerous growths attached to the wall of the colon). Suspicious polyps are often removed during a colonoscopy and, if necessary, a biopsy is performed. Undetected polyps can grow into malignant tumors. Many experts recommend men and women undergo a colonoscopy at age 50 with follow-up screenings. People with a family history of colorectal cancer or other risk factors should begin having colonoscopies at an earlier age.

Digital Rectal Exam: A digital rectal exam is performed at annual checkup.

Fecal Occult Blood Test (FOBT): Also known as a stool blood test, an FOBT is performed yearly to find hidden (occult) blood in the stool. If the test is positive, further tests, such as a colonoscopy, are performed to determine the cause of bleeding.

Flexible Sigmoidoscopy: The doctor uses a narrow, flexible, lighted tube to look at the inside of the rectum and the lower portion of the colon. During the exam, the doctor may remove some polyps (abnormal growths) and collect samples of tissue or cells for closer examination. This test is recommended every 5 years. (If polyps are found, you will need a follow-up colonoscopy.)

Diagnostic Imaging / Barium Enema with Air Contrast: To get high-quality x-rays of the colon, a chalky substance is used to partly fill and open the colon. Air is then pumped in to expand the colon.

Symptoms

Symptoms for colorectal cancer include:

  • A change in bowel habits (diarrhea, constipation, narrowing of stool) that lasts beyond a few days
  • Continuously feeling the need to move one’s bowels, even after doing so
  • Rectal bleeding or blood in the stool
  • Abdominal pain
  • Weakness and tiredness

Colorectal cancer can be effectively prevented with early detection and removal of polyps (abnormal growths) in the colon and rectum before they become malignant. Screening tests can find colorectal cancer early, when treatment works best and the chance for a full recovery is very high.

Diagnosis of Colorectal Cancer

Angiography

Physicians may perform an angiography to find blood vessels next to a cancer that has spread to the liver. This information is used to plan surgery that minimizes blood loss.

Biopsy

A biopsy involves removing a small tissue sample for a pathologist to examine under a microscope for cancer cells. This can take place during a colonoscopy or surgery.

Blood Tests

Blood tests are performed to check for the presence of CEA, a protein that acts as a marker for colorectal cancer. The CEA test is often used to diagnose a possible recurrence in people who have had colorectal cancer in the past. The CEA test does not diagnose early colon cancer and is not a substitute for colonoscopy.

Imaging Tests

Radiological tools used to diagnose and stage colorectal cancer include:

  • Computed tomography (CT)
  • Magnetic resonance imaging (MRI)
  • Chest X-ray
  • Positron-emission testing (PET scan)
  • Ultrasound

Treatment for Colorectal Cancer

Antibody Therapy

Man-made proteins called monoclonal antibodies, along with chemotherapy drugs, are used to treat colorectal cancer. Antibody therapies are targeted methods that attack parts of the cancer cells that distinguish them from normal cells.

Chemotherapy

Chemotherapy after surgery increases the cure rate for patients with early colorectal cancer. In more advanced cases, chemotherapy reduces the symptoms of cancer and prolongs survival.

Patients may experience fatigue while undergoing chemotherapy. If other symptoms arise, symptoms should call a physician or nurse right away.

Radiation Therapy for Colon and Rectal Cancer

Radiation therapy may be used before surgery for rectal cancer to shrink the tumor, making it more likely the surgeon can completely remove the tumor. Radiation is used in some cases after surgery if there are concerns that tumor cells were left behind.

Radiation may also be used to ease symptoms of advanced colon and rectal cancer.

Radiation therapy and chemotherapy are used as an alternative to surgery to cure anal cancers while sparing normal bowel function.

Surgery for Colon Cancer

Most patients with colon cancer undergo surgery. This usually involves removing a length of normal colon on either side of the tumor and some of the lymph nodes. Physicians connect the two ends of the colon. People with colon cancer do not generally need a colostomy (an opening in the abdomen to eliminate body waste), but they may have a temporary colostomy. Minimally invasive surgical procedures such as the laparoscopic removal of the colon can also be used to treat colon cancer.

Surgery for Rectal Cancer

Although surgery is the main treatment for rectal cancer, some patients may have radiation and chemotherapy before surgery. The type and extent of the surgery depends on the location and stage of the disease. While many patients with rectal cancer will require a colostomy, the chances of this are reduced due to preoperative chemotherapy and radiation, along with newer surgical techniques.

Yale School of Medicine

Yale New Haven Health is proud to be affiliated with the prestigious Yale University and its highly ranked Yale School of Medicine.