Double-contrast Barium Enema: Colorectal Cancer Screening

Double-contrast barium enema is a radiological technique that can be used to screen individuals for colorectal cancer. It is preferred in individuals who cannot undergo colonoscopy or are at an increased risk of complications from colonoscopy.

Prior to the procedure, the patient has to undergo bowel preparation with laxatives. Diet is also restricted for 1 to 2 days prior to the procedure. This ensures that the inner lining is clearly visible on x-ray. Incomplete evacuation of the bowels could result in the presence of small masses in the colon, and thus interfere with the interpretation of the test.

Following bowel preparation, the individual undergoing the test is made to lie down and an enema containing radioactive barium is administered. Subsequently, air is introduced through the anus through a thin tube. This ensures that the barium coats the inner lining of the colon. Images of the colon are obtained in the desired positions, which are then studied for any abnormalities.

Patients eligible for double-contrast barium enema

Double-contrast barium enema is especially preferred in individuals who cannot undergo procedures like colonoscopy or who are at an increased risk for complications if they undergo these procedures. A barium enema may be also required in patients who have undergone an incomplete sigmoidoscopy or colonoscopy.

Is there any need to repeat double-contrast barium enema?

Double-contrast barium enema may be repeated every 5 years. People at high risk for developing colorectal cancer may have to start undergoing the test at an earlier age and repeat it more often. 

Patients not eligible for double-contrast barium enema

Double-contrast barium enema is absolutely contraindicated during pregnancy due to the risk of radiation to the developing foetus. People with suspected perforation of the intestines, conditions that could lead to perforation such as severe ulcerative colitis or complete obstruction in the intestines should also avoid this test.

Pros of double-contrast barium enema

• The entire colon can be visualised during double-contrast barium enema
• The procedure permits visualisation not only of the inner lining of the colon on x-ray, but also detects any abnormalities within the wall of the colon as well as in the abdomen
• It helps to differentiate colorectal cancer from other conditions affecting the colon like diverticulitis
• It is more cost-effective as compared to colonoscopy
• Unlike procedures like flexible sigmoidoscopy and colonoscopy, there is minimal risk of perforation with this procedure

Cons of double-contrast barium enema

• The procedure exposes the person to radiation
• Bowel preparation with diet and laxatives is required prior to the procedure. This as well as the procedure itself may cause discomfort to the individual
• If the test detects any abnormality, the individual has to undergo a colonoscopy to obtain a biopsy or excise the lesion. Thus, doing two procedures instead of one increase the cost and inconvenience of the individual. This may be avoided in case a colonoscopy is done as the first choice
• The test may diagnose cancer in cases where it may not be present, resulting in unwanted anxiety in the individual. This could occur in case the radiologist is not experienced in interpreting the x-rays or if normal conditions like contractions or small faecal masses give the impression of a cancer
• Severe allergic reactions could rarely occur in patients allergic to barium