Colorectal cancer screening
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Colorectal cancer screening On the Web |
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American Roentgen Ray Society Images of Colorectal cancer screening |
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Risk calculators and risk factors for Colorectal cancer screening |
To view the screening of familial adenomatous polyposis (FAP), click here
To view the screening of hereditary nonpolyposis colorectal cancer (HNPCC), click here
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Elliot B. Tapper, M.D.; Saarah T. Alkhairy, M.D.
Overview
Current guidelines recommend that colonoscopy is the optimal screening tool for colon cancer since it detects 98-99% of the cases. High risk individuals include a first-degree relative with colorectal cancer. A colonoscopy every 10 years reduces the risk of left-sided colon cancer. Right sided colon cancers are more likely to be missed because they are harder to reach and they could be flat, which means they would be harder to detect. Flat growths (non-polypoid) are difficult to detect and are more likely to progress to colon cancer compared to cylindrical polyps.
Colorectal Cancer Screening
Early detection of premalignant colorectal masses or early-stage colorectal cancers is essential in treating these patients and possibly preventing cancer or colorectal cancer related death.
According to the USPSTF (United States Preventive Services Task Force):[1]
- Screening for colorectal cancer is recommended among adults older than 50 years of age and do not have an increased risk of developing the disease (average-risk adults).
- Decision to screen for colorectal cancer among adults aged 76 to 85 years is an individual one
- Screening would be more beneficial for healthier individuals that are able to undergo possible treatment
- Screening for colorectal cancer among adults aged 86 years and older is not recommended
- No preference is given to one screening modality over the other
- Decision should be shared and according to the patient's preferences when it comes to choosing an option
- Screening options:
- Colonoscopy
- FIT
- Fecal immunochemical testing for occult blood
- Flexible sigmoidoscopy
- Flexible sigmoidoscopy + FIT
- CT colonography
- FIT-DNA
- multitargeted stool DNA testing
- gFOBT
- Guaiac-based fecal occult blood testing
The most common indicator of high risk is a first-degree relative with colorectal cancer, a personal history of inflammatory bowel disease.[5]
- If the first-degree relative was diagnosed with CRC before 50 years of age
- The individual should be suspected of a hereditary syndrome
- A complete family history, genetic counseling and testing, and an appropriate timing for endoscopic surveillance should be obtained
- If a first-degree relative was diagnosed with CRC at 50 years of age or older the lifetime risk of CRC nearly doubles among his or her family members
The American College of Gastroenterology recommends:[6]
- Screening in African Americans should begin at age 45 years
- CT colonography every 5 years is the radiographic screening alternative, when patients decline colonoscopy
- Fecal immunochemical test for blood (FIT) is preferred over guaiac-based fecal occult blood testing
Types of Screening Methods
Fecal Occult Blood Testing
- A fecal occult blood test (FOBT) is a test for blood in the stool
- There are two types of tests that can be used for detecting occult blood in stools: guaiac-based (chemical test) and immunochemical
Endoscopy
- A sigmoidoscopy is a lighted probe (sigmoidoscope) that is inserted into the rectum and lower colon to check for polyps and other abnormalities
- A colonoscopy is a lighted probe (colonoscope) that is inserted into the rectum and the entire colon to look for polyps and other abnormalities that may be caused by cancer. A colonoscopy has the advantage that if polyps are found during the procedure they can be immediately removed, and the tissue can also be taken for biopsy. The American Society for Gastrointestinal Endoscopy has released quality indicators for screening colonoscopy, which include:[7]
- Documentation of prep quality
- Photo documentation of cecal intubation
- Withdrawal time of 6 minutes or more
- Adenoma detection rate of greater than 25% in males and 15% in females greater than 50 years old.
Genetic Testing
- Genetic counseling and genetic testing is a screening modality for families who may have a hereditary form of colon cancer, such as hereditary nonpolyposis colorectal cancer (HNPCC) or familial adenomatous polyposis (FAP)
Other Screening Techniques
- Double contrast barium enema (DCBE)
- First, an overnight preparation is taken to cleanse the colon.
- An enema containing barium sulfate is administered, then air is insufflated into the colon, distending it.
- The result is a thin layer of barium over the inner lining of the colon which is visible on X-ray films.
- A cancer or a precancerous polyp can be detected this way.
- This technique can miss the (less common) flat polyp.
- This is also known as CT colonography
- This replaces X-ray films in the double contrast barium enema (above) with a special computed tomography scan.
- It requires special workstation software in order for the radiologist to interpret.
- This technique is approaching colonoscopy in sensitivity for polyps. However, any polyps found must still be removed by standard colonoscopy.
- The measurement of the patient's blood for elevated levels of certain proteins can give an indication of tumor load.
- High levels of carcinoembryonic antigen (CEA) in the blood can indicate metastasis of adenocarcinoma.
- These tests are frequently false positive or false negative, and are not recommended for screening, it can be useful to assess disease recurrence.
- Stool DNA testing
- This detects DNA that sheds into the stool from the cells of pre-malignant adenomas and cancers.
- The DNA is not degraded during the digestive process and remains in the stool.
References
- ↑ US Preventive Services Task Force. Bibbins-Domingo K, Grossman DC, Curry SJ, Davidson KW, Epling JW; et al. (2016). "Screening for Colorectal Cancer: US Preventive Services Task Force Recommendation Statement". JAMA. 315 (23): 2564–2575. doi:10.1001/jama.2016.5989. PMID 27304597.
- ↑ https://www.rmf.harvard.edu/~/media/Files/_Global/KC/PDFs/RMFCRC.pdf
- ↑ https://www.rmf.harvard.edu/~/media/Files/_Global/KC/PDFs/RMFCRC.pdf
- ↑ https://www.rmf.harvard.edu/~/media/Files/_Global/KC/PDFs/RMFCRC.pdf
- ↑ Lieberman, David A. (2009). "Screening for Colorectal Cancer". New England Journal of Medicine. 361 (12): 1179–1187. doi:10.1056/NEJMcp0902176. ISSN 0028-4793.
- ↑ Rex DK, Johnson DA, Anderson JC, et al. American College of Gastroenterology guidelines for colorectal cancer screening 2009.Am J Gastroenterol. 2009 Mar;104(3):739-50.
- ↑ Rex DK, Petrini JL, Baron TH, Chak A, Cohen J, Deal SE; et al. (2006). "Quality indicators for colonoscopy". Am J Gastroenterol. 101 (4): 873–85. doi:10.1111/j.1572-0241.2006.00673.x. PMID 16635231.