What is Colorectal Cancer (CRC)?

Colorectal cancer (CRC), sometimes referred to as colon cancer, is cancer that grows in the colon or rectum. While abnormal masses of cells in other types of cancer are called tumors, the masses in colorectal cancer are called polyps.

Your colon and rectum are part of your gastrointestinal (GI) system tasked with expelling food after your body has absorbed the nutrients.  

What are signs and symptoms of colorectal cancer?

The following can be signs and symptoms of colorectal cancer, but other conditions can come across in the same way. Make an appointment with your doctor if you notice any of the following:

  • Blood in your stool—regardless of whether bright red or very dark red
  • General discomfort in your belly, such as bloating, gas pains, fullness, and cramps
  • Changes in your appetite
  • Losing weight for no reason
  • Feeling really tired
  • Change in your bowel habits or if you are experiencing:
    • Constipation
    • Diarrhea
    • A bowel does not empty out completely when you have a bowel movement
    • Changes in the stool shape (for example, it is narrower than usual

How is CRC diagnosed and treated?

The United States Preventive Services Task Force (USPSTF) recommends that all adults ages 50 to 75 years old get screened for CRC. The USPSTF also encourages people 45 to 49 years of age to get screened, but the recommendation is not quite as strong. The purpose of a screening test is to find abnormal growths in the colon, called polyps, and remove them before they turn cancerous.

Colorectal cancer screenings are recommended as follows:

  • Individuals age 45 or older for those of average risk
  • Individuals with a high/increased risk of colorectal cancer. This includes those who have:
    • Any first-degree relative who was diagnosed with colorectal cancer or a high-risk polyp. They should have a colonoscopy beginning at age 40 or at 10 years younger than the age at diagnosis of the youngest affected relative.
    • A relative who was diagnosed younger than age 60, or has 2 first-degree relatives who were diagnosed with colorectal cancer, then screening should occur every 5 years.
    • A relative who was diagnosed older than age 60, then screening can follow average risk screening intervals.
  • For increased risk factors such as Crohn’s disease or ulcerative colitis, seek the advice of your gastroenterologist

Consult with your doctor on the best screening test for you. Each test has pros and cons. Some have a higher risk of false positives or may not screen the entire colon. Your doctor will explain  which screening test(s) he or she feels is most appropriate for you, its benefits, and its risks.

Common Screening Tests

  • Stool Tests
    • Guaiac-based fecal occult blood test (gFOBT) is a yearly test that uses a chemical called guaiac to detect blood in your stool. While the test is done at home, you must get the test kit from your doctor. After you collect a small sample of your stool using a stick or a brush, you send the kit to your doctor or lab where they check your stool sample.
    • Fecal Immunochemical Test (FIT) is a yearly test that uses special immune cell proteins called antibodies to detect blood in your stool.
    • FIT— This test requires you to collect the stool from a complete bowel movement and send it to a lab where scientists check the stool for cancer. 
  • Flexible Sigmoidoscopy is a procedure where your doctor inserts a small tube with light into your rectum allowing your doctor to see inside the lower third of your colon to check for polyps or cancer. Your doctor will recommend this test every 5 years.
  • Colonoscopy is very similar to the flexible sigmoidoscopy.  If you don’t have an increased risk for colorectal cancer, you’ll get a colonoscopy every 10 years.
  • Computed Tomography (CT) Colonography or Virtual Colonoscopy): This procedure uses computers and X-ray machines to give your doctor pictures of your entire colon so he or she can check for abnormal tissue. CT colonographies are done every 5 years.

Endoscopic ultrasound (EUS) is used to examine the organs of the digestive tract and the surrounding tissue and organs. Information about the layers of the intestinal wall and adjacent areas including lymph nodes and blood vessels can also be obtained using EUS.

During the procedure, a tissue sample of suspicious tumors or enlarged lymph nodes may be obtained under EUS guidance so that they may be examined under a microscope by a pathologist. This is called a fine needle aspiration (FNA) and is an alternative to exploratory surgery or other invasive testing.

Endoscopic ultrasound is especially useful in the diagnosing and staging of cancers of the esophagus, stomach, duodenum, rectum, pancreas, and sometimes lung. Information regarding the depth of penetration and spread of cancer to adjacent tissues and lymph nodes can be obtained using EUS. Masses or cysts of the pancreas and chronic pancreatitis may also be evaluated using EUS. Bile duct abnormalities, including stones in the bile duct or gallbladder can be studied using endoscopic ultrasound. The procedure is also useful for studying bile duct, gallbladder, or liver tumors. EUS may help discover reasons for fecal incontinence when used to examine the sphincter muscles of the lower rectum and anal canal. Abnormalities, such as lesions or nodules that may be hiding in the intestinal wall beneath normal-appearing intestinal tract lining may also be studied using EUS (“submucosal” or “subepithelial” lesions).