March 25, 2019

Colon Cancer Screening Saves Lives by Mahesh C. Karamchandani, MD, FACS, FASCRS, FICS

March 2019

Dr. karamchandani

There are only a few types of cancers that are preventable and colon and rectal cancer is one of them. Regular screening has been shown to reduce the incidence of colorectal cancer. As we observe National Colon and Rectal Cancer Awareness Month in March, make a choice of screening and beat this cancer.

Colon and rectal cancer is the third leading type of cancer and the second leading cause of cancer related deaths in United States for men and women combined.  The general population faces a lifetime risk for developing the disease of about 5%, while someone with family history of colorectal cancer has about three times higher risk.  The risk rises to over 50% in people with ulcerative colitis and those whose family member harbors specific genetic mutation.

Colorectal cancer is often a silent disease developing with no symptoms.  When symptoms develop, they include blood in stool, change in bowel habits, stools that are narrower than usual, stomach discomfort, vomiting, diarrhea, constipation, feeling that the bowel does not empty completely, unexplained weight loss, and constant tiredness.

Colorectal cancer is diagnosed by physical examination, barium enema, colonoscopy, and CT scan.  Between 80 and 90% of colorectal cancer patients are restored to normal health if their cancer is detected and treated in earlier stages.  However, cure rate drops to 50% or less when cancer is diagnosed at a later stage.  Unfortunately, only 37% of colorectal cancers are discovered in early stages.  

Colorectal cancer is one of the most preventable form of cancers.  With lifestyle modification and regular screening one can reduce the risk of developing colorectal cancer.  The majority of colorectal cancers arise from polyps, which when small, do not cause any symptoms.  Polyps detected and removed when small offer the best prevention.  Finding polyps early can reduce the risk of cancer by up to 90%.  Hence regular screening is of utmost importance.

For people with average risk and without any symptoms, the American Cancer Society recommends regular screening for colorectal cancer starting at the age of 50 with either a high‐sensitivity stool‐based test or a visual examination, depending on patient preference and test availability.  Options for colorectal cancer screening include the following:

 Stool‐based tests

  • High‐sensitivity, guaiac‐based fecal occult blood test (gFOBT) every year– This test detects hidden blood in the stool.  Some foods or drugs can affect the results of this test and need to be stopped prior to submitting the stool specimen.  Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil), naproxen (Aleve), or aspirin should be stopped for seven days; Vitamin C supplements, citrus fruits and juices for three days; and red meats (beef, lamb, or liver) for three days.
  • Fecal immunochemical test (FIT) every year– Also called an immunochemical fecal occult blood test (iFOBT), it tests for hidden blood in the stool by detecting human hemoglobin protein, which is found in red blood cells.  Unlike the gFOBT, there are no drug or dietary restrictions before the test as vitamins and foods do not affect the FIT, which makes collecting the samples easier.
  • Multitarget stool DNA test every 3 years– Commonly known as Cologuard, this testdetects abnormal DNA in addition to fecal hemoglobin.  The stool DNA test correctly identifies 92% ofcolorectal cancers and 69% ofpolyps with premalignant features.  False positives and false negatives occur with Cologuard and appropriate follow-up is important. 

      If any of these tests are positive, colonoscopy is required in timely fashion.

Visual examinations

  • Colonoscopy every 10 years– During a colonoscopy, a long, flexible tube with fiberoptics is inserted through the rectum into the colon.  A tiny video camera at the tip of the tube allows the doctor to view the inside of the entire colon.
  • Flexible sigmoidoscopy every 5 years– This test checks only half of the colon.  If polyps are found,colonoscopy is required for their removal and to check the rest of the colon.
  • CT colonography every 5 years– Also known as virtual colonoscopy, this testis a CT scan that takes 3-D images of the colon.  Preparation is the same as for colonoscopy and air is used to distend the bowel.  The disadvantage of this test over colonoscopy is that sedation is not provided and if a polyp or growth is seen biopsy or removal cannot be one. 

The ACS recommends that average‐risk adults in good health with a life expectancy of greater than 10 years continue colorectal cancer screening through the age of 75 years. For individuals aged 76 through 85 years, the ACS recommends that screening be based on patient preferences, life expectancy, health status, and prior screening history.  Recently, the American Cancer Society (ACS) released an updated guideline recommending that colorectal cancer screening begin at age 45 for patients at average risk.

If there is family history of colorectal cancer in a first degree relative, colonoscopy is recommended every five years starting at age 40 or ten years before that relative developed colorectal cancer, whichever comes first.  If you have a personal history of polyps, colorectal cancer, or chronic inflammatory bowel disease of over seven years’ duration, you need more frequent evaluation.  However, if you have any of the symptoms described above, please see your healthcare provider immediately.

Colorectal cancer screening costs are covered by Medicare and many commercial health plans.  You should talk to your healthcare provider about which screening procedure is right for you and how often you should be screened.

Mahesh C. Karamchandani, MD is a Colon and Rectal Surgeon with Bronson Center for Colon and Rectal Diseases and Chair of Calhoun County Cancer Control Coalition.