The American Cancer Society and Colorectal Cancer Screening

Colorectal cancer is the fourth most common cancer with 140,000 diagnoses in the nation annually. It causes 50,000 deaths per year and is the number two cause of death due to cancer.

Colorectal cancer screening guidelines have called for digital rectal examinations beginning at age 40 and colonoscopies at age 50 in low risk individuals. An aggressive public awareness campaign has resulted in a marked decrease in deaths from this disease in men and women over age 65.

The same cannot be said for men and women younger than 55 years old where there is an increased incidence of colorectal cancer by 51% with an increased mortality of 11%. Experts believe the increase may be due to lifestyle issues including tobacco and alcohol usage, obesity, ingestion of processed meats and poorer sleep habits.

To combat this increase, the American Cancer Society has changed its recommendations on screening suggesting that at age 45 we give patients the option of:

  • Fecal immunochemical test yearly
  • Fecal Occult Blood High Sensitivity Guaiac Based Yearly
  • Stool DNA Test (e.g., Cologuard) every 3 years
  • CT Scan Virtual Colonoscopy every 5 years
  • Flexible Sigmoidoscopy every 5 years
  • Colonoscopy every 10 years.

Their position paper points out that people of color, American Indians and Alaskan natives have a higher incidence of colon cancer and mortality than other populations.  Therefore, these groups should be screened more diligently. They additionally note that they discourage screening in adults over the age of 85 years old. This decision should be individualized based on the patient’s health and expected independent longevity.

As a practicing physician these are sensible guidelines. The CT Virtual Colonoscopy involves a large X irradiation exposure and necessitates a pre- procedure prep. Cologuard and DNA testing misses few malignancies but has shown many false positives necessitating a colonoscopy. Both CT Virtual Colonoscopy and Cologuard may not be covered by your insurer, and they are expensive, so consider the cost in your choice of screening.

I still believe Flexible Sigmoidoscopy must be combined with the Fecal Occult Blood High Sensitivity Testing and prepping.  Looking at only part of the colon makes little sense to me in screening.

Colonoscopy is still the gold standard for detecting colorectal cancer.

March Is Colon Cancer Awareness Month

Colon CancerColon Cancer is still the second leading cause of death from cancer in the United States despite numerous advances in screening and early detection. It is a disease that is found more commonly in black Americans with 46.7 cases per 100,000 individuals as compared to 38.9 cases per 100,000 individuals for Caucasian Americans. Death from colorectal cancer occurs in every 21.1 cases for African Americans and only 14.6 cases for white Americans.

Even with these dismal figures the cancer death rate from this disease has decreased by 22 percent over the last decade. We attribute this to increased awareness and increased screening.

All individuals should report a change in bowel habits to their doctor immediately. Blood stained stool is a cause for an immediate call to your physician. Generally at age 40 all adults should be having a digital rectal examination as part of a checkup. Stool occult blood slides or stool fecal immunoglobulin slides are used to screen for microscopic gastrointestinal tract bleeding. These tests involve placing a small smear of stool on a slide and submitting it to the lab where it is tested for microscopic blood loss. Usually a CBC or complete blood count is performed as well since gastrointestinal blood loss in small constant amounts usually produces a low blood count or anemia of the iron deficient variety.

Screening colonoscopies are recommended for all non-Black Americans at age 50. Due to the increased risk of colon cancer in Black Americans we recommend that they start screening colonoscopies at age 45. If you have a first degree relative who had colon cancer or precancerous polyps we ask that you start your screening at an age that is 10 years earlier than your relatives disease became apparent.

For those individuals unwilling to have a screening colonoscopy we can offer a CT Virtual Colonoscopy. The preparation is simpler than for a colonoscopy but the radiation dosage involved is equivalent to receiving ten years’ worth of chest x-rays all at once. If the virtual colonoscopy shows a polyp or a mass you will then need to undergo a traditional colonoscopy for biopsy and removal preceded by a traditional pre- colonoscopy bowel cleansing prep.

Cologuard is a new and attractive stool test that detects abnormal DNA associated with premalignant polyps and cancerous tumors. It is fairly new but readily available.

Numerous lifestyle choices can influence your development of colon cancer. Tobacco use is associated with an increased risk, as is drinking more than moderate alcohol. Red meat intake is associated with an increased risk of colon cancer with a 20% increase per 100 gram increase in red meat per day. Regular exercise and intake of high fiber food helps to decrease your risk of developing colon cancer.

March is colon cancer awareness month. Speak to your physician about your risk of developing this serious disease and ways to prevent it from developing. You can use the visit to establish your own personalized colon cancer screening surveillance schedule.

New Test for Colon Cancer Screening Approved

Colon Cancer RibbonThe Cologuard test is the first DNA based screening test for colorectal cancer that has received approval for use from the FDA and preliminary approval by Medicare to cover the cost of the test. The test detects hemoglobin ( a component of red blood cells) and abnormal DNA in cells picked up by stool . A positive test indicates a need for colonoscopy to identify or eliminate colon cancer as a possibility. We currently screen patients with the fecal occult blood slide test and the more sophisticated fecal immunochemical test or FIT. The new Cologuard detected 92% of colon cancers and 42% of advanced adenomatous colon polyps as compared with 74% and 24 % for FIT. While the Cologuard test was accurate in picking up more colon cancers than the FIT it had slightly more false positive tests than the traditional Fecal Occult Blood Slide.

The Center for Medicare Services ( CMS) is proposing allowing coverage of the DNA test once every three years for beneficiaries who are 50 – 85 years old, asymptomatic and have average risk of colorectal cancer. The new test adds another non-invasive means of screening for colon cancer. We will need to see the cost of the test to the individual patient and accumulate more data on its accuracy in the near future before it becomes a mainstay of colon cancer screening.

At the same time that Cologuard was approved, researchers at the University of Michigan in Ann Arbor published in the online journal Cancer Prevention Research, information showing that evaluation of the pattern of bacteria in the colon of patients improved performance and detection of colon cancer by more than 50% as compared to the Fecal Occult Blood Test alone. Researchers using DNA sequencing and polymerase chain reaction methods were able to identify distinctly different patterns of bacteria in colon cancer and pre-cancerous polyps than in patients with no colon lesions.

It is clear that as researchers apply DNA technology to cancer screening their ability to detect abnormalities and avoid invasive colorectal screening will improve. At the moment recommendations for screening colonoscopy at age 50 remain but as science moves forward that too may soon change.