Colorectal Cancer

Colorectal Cancer Awareness

According to the Centers for Disease Control and Prevention (CDC), colorectal cancer is the second leading cause of cancer deaths amongst those cancers that affect both men and women.  Annually, 140,000 Americans will be diagnosed with colorectal cancer, and 50,000 will die from it.

Symptoms of Colorectal Cancer

Early stages of colorectal cancer often do not cause symptoms.  Symptoms vary and are dependent on the location of the cancer in the large intestine.  

Symptoms may include:

  • A change in bowel habits, such as diarrhea, constipation, or in the consistency of the stool, that lasts longer than four weeks
  • Rectal bleeding
  • Weakness or fatigue
  • Unexplained weight loss
  • A feeling that the bowel has not been completely emptied
  • Abdominal discomfort

When these symptoms are noticed, they should be discussed with a physician.

Causes of Colorectal Cancer

Generally, there is no known cause of colorectal cancer.  However, there are risk factors that can increase the risk of developing colorectal cancer.

Inherited genes are linked to a small percentage of colorectal cancers.  Having these genes does not necessitate a diagnosis of colorectal cancer, but it does greatly increase the risk.  The most common inherited colorectal cancer syndromes are:

  • Hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome, increases the risk of several different types of cancer.  People with HNPCC are likely to develop colorectal cancer earlier in life – before the age of 50.
  • Familial adenomatous polyposis (FAP) causes thousands of polyps to form in the colon and the rectum.  FAP generally occurs before the age of 40.

Diet is currently being studied.  It appears as if the standard Western diet may contribute to an increased risk of colon cancer.  According to Mayo Clinic, “When people move from areas where the typical diet is low in fat and high in fiber to areas where the typical Western diet is most common, the risk of colon cancer in these people increases significantly.”  Two theories are that the Western diet may lead to inflammation and that it may affect the microbes that life on the colon.

Other risk factors include:

  • Being over the age of 50
  • Being African-American; African-Americans tend to develop colorectal cancer more frequently than other races
  • Having other inflammatory bowel conditions, such as Crohn’s disease or ulcerative colitis
  • Living a sedentary lifestyle
  • Being a smoker
  • Being obese
  • Having diabetes
  • Drinking excess alcohol
  • Having a prior history of being treated with radiation therapy to the abdomen

Prevention of Colorectal Cancer

It has been proposed that consuming a low-fat, high-fiber diet may reduce the risk of developing colorectal cancer.  For example, eating a diet rich in fruits in vegetables may be helpful, as well as a diet that is low in animal fats.  Improving the quality of fats, such as omega-3s, may be helpful.

Some experts recommend taking an aspirin for those that are at an increased risk of colorectal cancer because it may stop cancer cells from multiplying.

Screening for Colorectal Cancer

However, the most powerful tool to prevent colorectal cancer from occurring is regular screening for colorectal cancer.

According to the CDC, the U.S. Preventive Services Task Force recommends that all adults between the ages of 50 and 75 should be screened for colorectal cancer; adults older than 75 may be screened based on an individual basis.

Based on your general health and health history, your physician will recommend a screening tool that is right for you.

Stool tests include:

  • Guaiac-based fecal occult blood test (gFOBT) can be done at home and returned to a lab.  It uses the chemical guaiac to detect blood in stool.
  • Fecal immunochemical test (FIT) is performed in the same way as a gFOBT.  This test uses antibodies to detect blood in stool.
  • FIT-DNA test evaluates an entire bowel movement for cancerous cells.

If stool tests are being used to evaluate for colorectal cancer, gFOBT is typically performed yearly, while the FIT tests may be performed every three years.


Endoscopy procedures include:

  • Flexible sigmoidoscopy is performed by a physician inserting a thin tube into the rectum.  This tube allows the physician to evaluate the rectum and bottom portion of the colon for polyps and cancerous cells.  A flexible sigmoidoscopy is typically performed every five years, of every 10 years with a FIT test.
  • Colonoscopy is performed by a physician inserting a thin tube into the colon.  The procedure is like a flexible sigmoidoscopy, but the entire rectum and colon is visualized.  Because the entire colon is visualized, cancer and polyps can be removed during the procedure. A colonoscopy is performed every 10 years.
  • CT colonography utilizes computed tomography (CT) to visualize the entire colon.  CT colonography is performed every five years.

Screening tests can save lives – colorectal cancer typically begins as a precancerous growth called a polyp.  Without treatment, polyps often turn into cancer.  When screening detects these polyps, they can be removed before cancer begins.


Centers for Disease Control and Prevention.  (2019, March 5). Colorectal cancer awareness.  Retrieved from

Centers for Disease Control and Prevention.  (2017, April). Colorectal cancer screening.  Retrieved from

Mayo Clinic.  (2018, November 15).  Colon cancer – overview.  Retrieved from

WebMD.  (2018, July 9).  Preventing colorectal cancer.  Retrieved from

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