Overview

Colorectal cancer is cancer that starts in the colon or rectum, the last part of the digestive system. Most cases begin as small growths called polyps that slowly turn into cancer over several years. Early colorectal cancer often causes no symptoms.

Screening can find and remove polyps before they become cancer, or find cancer early, when treatment is most effective. The USPSTF and the American Cancer Society advise people at average risk to start screening at age 45. Cases are rising in adults younger than 50, so new bowel symptoms deserve attention at any age.

Symptoms

• Blood in the stool or bleeding from the rectum
• A change in bowel habits lasting more than a few weeks, such as diarrhea, constipation or narrower stool
• A feeling that the bowel does not empty fully
• Belly pain, cramps or bloating that does not go away
• Tiredness caused by iron-deficiency anemia
• Weight loss without trying
• Warning signs that need urgent care: black stool, heavy bleeding, or severe belly pain with vomiting

Causes & Risk Factors

• Age 45 and older, with risk rising with age
• A parent, brother, sister or child with colorectal cancer or advanced polyps
• Past polyps, or inflammatory bowel disease such as ulcerative colitis or Crohn's disease
• Inherited syndromes such as Lynch syndrome or familial adenomatous polyposis
• Excess weight, low physical activity and type 2 diabetes
• A diet high in red and processed meat and low in fiber
• Tobacco smoking, including shisha, and alcohol

Complications

• Bowel blockage, causing belly swelling, pain and vomiting
• Heavy bleeding or ongoing anemia
• A tear in the bowel wall (perforation), which is an emergency
• Spread of cancer to the liver, lungs or other organs
• A temporary or permanent stoma (bowel opening on the belly) after some operations

Diagnosis

Screening options for people at average risk include a yearly stool immunochemical test (FIT), a stool DNA-FIT test every 1 to 3 years, colonoscopy every 10 years, or CT colonography every 5 years. Any positive stool test must be followed by a colonoscopy. People with a parent, sibling or child who had colorectal cancer usually start colonoscopy at 40, or 10 years before the relative's age at diagnosis, whichever comes first. When symptoms are present, colonoscopy with biopsy confirms the diagnosis, and CT or MRI scans show whether the cancer has spread.

Treatment

• Removal of polyps and some very early cancers during colonoscopy
• Surgery to remove the affected part of the colon or rectum and nearby lymph nodes
• Chemotherapy before or after surgery, depending on the stage
• Radiotherapy, mainly for rectal cancer
• Targeted therapy or immunotherapy for certain cancer types, based on tumor testing
• A plan made by a team of specialists, with regular follow-up colonoscopy and scans

Prevention

• Start screening at 45 at average risk, and earlier with a family history or other risk factor
• Keep up regular screening until age 75, then decide with a doctor about screening between 76 and 85
• Eat plenty of fiber, vegetables, fruit and whole grains
• Limit red and processed meat
• Stay active and keep a healthy weight
• Avoid smoking, including shisha, and alcohol

The Internal Medicine and General Surgery departments at AlHayat Medical Center assess bowel symptoms and advise on colorectal cancer screening.

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