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.
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
Direct visualization screening tests and their interval
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:
- People who have at least one first-degree relative with a history of advanced adenoma or CRC diagnosed before 60 years.
- 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.