Colorectal cancer (CRC) is the third most regular cancer growth among inhabitants in the United States, and it is the second most frequent cause of death. There have been around 50,000 deaths from CRC in the year 2014 alone. However, the mortality rates have declined since then, owing to screening test measure for early detection and treatment, and prevention through polypectomy. There are certain risk factors associated with CRC which is modifiable such as smoking, obesity, alcohol, and low-fiber, high-fat diet.
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Colorectal Cancer

Image: “Location and appearance of two examples of colorectal tumors” by Blausen Medical Communications, Inc. License: CC BY 3.0


Screening of CRC

Screening for any cancer is done before the appearance of symptoms. The most obvious advantage of this process is to detect any underlying cancer at an early stage and therefore reducing the mortality rate through preventing the disease from getting to the advanced stage. Modern screening tests can meet this goal as they can detect early stage adenocarcinomas and adenomatous polyps. Adults beyond 50 years old are more likely to have adenomatous polyps which are related to higher chances of having a colorectal tumor. The survival rate on account of CRC is as per the following:

  • If CRC is diagnosed while it is as yet limited to the bowel walls, the survival rate is 90 percent.
  • 68% if there is lymph node involvement but no metastasis.
  • 10% in the case of distant metastasis.

When to screen and for how long

The screening for CRC ought to start at 50 years old; 45 in the case of black adults. As per The U.S. Preventive Services Task Force (USPSTF) recommendations, this screening should continue until the age of 75. However, after the age of 75 years, screening is not usually recommended. To screen or not to screen becomes an individualized decision after the age of 75 years. The decision is based on the overall health of the patient and prior screening.

Screening tests are of following two types

  • tests for cancer prevention
  • tests for cancer detection

Cancer prevention tests are preferred over cancer detection tests for obvious reasons.

Screening Tests

Following three categories of individuals probably benefit more from the screening tests:

  • Adults with no past screening history
  • Individuals who are capable of receiving cancer treatment if diagnosed as a CRC case.
  • Individuals who are free of life-limiting conditions.

American Academy of Family Physicians (AAFP) recommendations:

The AAFP suggests screening for colorectal cancerous growth at 50 years. The screening should continue for as long as 75 years of age. The proposed tests for screening purpose are fecal immunochemical tests, flexible sigmoidoscopy, and colonoscopy.

The dangers, advantages, and strength of the supporting confirmation of various screening techniques differ.

The decision for screening in the age group 76-85 years is an individual one. The general health of the patient and past screening history are considered before settling on screening choice.

The American Academy of Family Physicians does not recommend screening for CRC in older adults after the age of 85 years.

U.S. Preventive Services Task Force (USPSTF) recommendations:

USPSTF rules for colorectal disease screening are the ones given by the American Academy of Family Physicians.

The guidelines also include a range of tests presented in Table 1.0.

Table 1.0. Screening tests for colorectal cancer screening

Stool-based screening tests and their interval

  • A guaiac-based fecal occult blood test is used for screening purpose at an interval of one year.
  • The fecal immunochemical test is repeated every year.
  • Multitarget stool DNA test with a fecal immunochemical test is recommended every 1 or 3 years

Direct visualization screening tests and their interval

  • Colonoscopy is recommended every 10 years for screening purpose.
  • Computed tomographic colonography and Flexible sigmoidoscopy are repeated every 5 years.
  • Flexible sigmoidoscopy with the fecal immunochemical test is recommended based on repeating the procedure every 10 years for Flexible sigmoidoscopy and 1 year for FIT.

American College of Gastroenterology (ACG) recommendations

ACG recommendations contrast between the screening tests and the identification tests for CRC. Specific ACG guidelines are given below.

  • Tests used for cancer prevention are preferred over diagnostic tests.
  • Screening tests ought to start at age 50; at age 45 in the case of African Americans. The preferred test is colonoscopy at an interval of every 10 years.
  • If the patient refuses colonoscopy and other screening tests, he should be suggested yearly fecal immunochemical test (FIT).

According to ACG recommendations, taking after two classifications of individuals ought to experience colonoscopy starting at age 40 and to repeat every 5 years:

  1. People who have at least one first-degree relative with a history of advanced adenoma or CRC diagnosed before 60 years.
  2. Individuals who have two first-degree relatives diagnosed with advanced adenoma or CRC

Interval for following colonoscopy results

  • Cases of villous adenoma and high-grade dysplasia should have a follow up every three years.
  • Dysplasia in sessile serrated polyp has a three-year follow-up period.
  • Large serrated adenoma should have follow-up colonoscopy every 5-10 years
  • Individuals with more than ten adenomas ought to have a colonoscopy before three years of the last follow-up.
  • In the case of status post, piecemeal resection of large adenoma follow-up is recommended within less than a year.
  • Status post curative resection of large CRC cases should undergo follow-up 3 and 5 years after the resection.
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