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Colorectal Cancer Screening

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Colorectal cancer is a painful disease wherein the cells of the rectum divide abnormally to form tumours and polyps. The initial symptoms often go unnoticed, but after detecting any abnormality, doctors usually suggest to undergo colorectal cancer screening. We shall discuss the screening procedure in details in the upcoming content.

When to take up the test?

Usually a colorectal screening is advised to men and women above 45 years of age who have had a family history. Screening tests must also be performed when you observe the following symptoms:

  • Blood in stool
  • Itching and pain in rectum while passing stool
  • Severe constipation
  • Tenderness in lower abdomen
  • Abnormal stools
  • Random weight loss

Points to note:

  • Colorectal screening test is a must for people with inflammatory bowel disease and it is performed usually after one year on those who have undergone surgery for colorectal cancer.
  • Anal flexible sigmoidoscopy must also be performed in the age group of 10-12 years on those with family history of familial adenomatous polyposis.

Objectives of Colorectal Cancer Screening

The main objective of the tests is to detect colorectal cancer at an early stage even if symptoms are not evident. This ensures early diagnosis of the cancer and 100% recovery. The ultimate outcome is – “saving lives of many”. Other than cancer, they also check for polyps and other abnormalities in the rectum which could be cured by treatment.

Types of Colorectal Cancer Screening Tests

1.Colonoscopy

Colonoscopy is a longer version of sigmoidscopy. It involves complete analysis of the colon and the rectum with the help of a colonoscope, inserted via rectum. A camera is attached at the end of the colonoscope which is connected to a computer outside where your doctor can view the condition of your colon and rectum. During this process, a sample can be collected for biopsy purpose or polyps can be removed. The entire process will take around 30 minutes and before the test you will be given a mild sedative.

2.Flexible sigmoidoscopy

The basic procedure is same as colonoscopy. The only difference is that the sigmoidscope is only 60 cms long, which is inserted into the rectum to view your entire rectum and part of the colon. Your doctor will not take more than 15 to 20 minutes for this. In most cases patients are not given sedatives, but a preliminary digital rectal exam is performed for easing insertion of the sigmoidscope. Colorectal cancers and polyps get easily detected with this technique.

3.Virtual Colonoscopy or CT Colonography

As the name suggests, an imaging technique computerized tomography (CT) is used to procure cross-sectional or 3-D view of the large intestine and the rectum. The colon is enlarged by inserting a catheter filled with air through the rectum, which is painless. The test gives clear picture of the abdominal organs and it can detect how far the cancer has spread in only 10 minutes.

Other Tests that are also a Part of the Screening:

  • Fecal Occult Blood Test (FOBT): also termed as stool DNA test (sDNA) or fecal immunochemical test (FIT)- involves testing the stool for hidden blood
  • Double-contrast Barium Enema: involves use of barium sulfate solution pumped inside the intestine to get X ray of the colon and intestine
  • How to Prepare for the Screening Tests
  • Do not get tensed or apprehensive about the screening test. Your doctor will examine you and then decide which test you need to undergo.
  • Secondly, consult with your doctor about your health problems, if you are taking any medicines or laxatives and also if you are pregnant
  • Your rectum and colon should be empty. A day before the exam you may be asked to cleanse your colon with special fluids
  • You may be given sedatives before the screening is done

Possible Risks of Colorectal Cancer Screening Tests

Colorectal screening is the only way to detect cancer in colon and rectum. However, in some cases it can fall out for the following reasons:

  • False Negative: The fecal occult blood test sometimes shows a false negative test wherein the patient has cancer but the test shows negative
  • False Positive: This is just the opposite of false negative. The patient is diagnosed with false cancer when she/he doesn’t have it.  In such cases further tests are suggested for more accuracy.
  • During the tests, especially during colonoscopy and sigmoidoscopy, the patient may undergo lower abdominal pain, anal pain and feel urge to pass bowel. Dizziness and nausea are some other side effects.

However, these side effects are not a major concern. In most cases the tests are accurate and are the best diagnostic measures to start an early treatment for colorectal cancer.

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Written by: Saptakee sengupta
Date last updated: January 04, 2015