 additional screening for DNA cells that are shed from the colon and the rectum during a bowel movement. Cologuard is a commonly used brand for this test. Upon receipt, the lab extracts DNA from the stool to identify whether or not mutated or abnormal genes are present. This test collects a full stool sample and does not require dietary changes.
Whatever test is used, it should not be used by women who are menstruating—testing while on your period can produce a false positive.
What the Results Mean for You
Blood in the stool does not necessarily mean you have cancer. There are many other conditions, such as IBD, ulcers, hemorrhoids, colon polyps, or anal fissures, that could be contributing to gastrointestinal bleeding. If blood is found, your doctor will likely recommend additional testing to determine the cause of your positive test result.
Additionally, tests such as Cologuard will look for genetic changes that could signal the presence of colorectal cancer. The results will indicate if any mutations are present.
If you receive a negative test, no blood was found in the sample, and no genetic changes were noted.
Should you receive inconclusive — neither positive nor negative — results, it’s possible that there was an issue with your specimen. In cases such as this, your primary care physician might recommend testing again.
Your doctor will be able to discuss the risks of receiving either a false-positive or false-negative result. Despite the risk, the National Cancer Institute points to probable benefits, “Studies show that some screening tests for colorectal cancer help find cancer at an early stage and may decrease the number of deaths from the disease.”
Visual Tests Used for Colorectal Cancer Screening
While there are advantages to at-home colon cancer tests, they also have some disadvantages. Even though convenient and non-invasive, at-home tests aren’t as accurate as other types of colon cancer screening. Their higher probability of false positives and false negatives means that you’re likely to need follow-up testing anyway. At-home tests can also be difficult to administer for some people. When tests aren’t administered accurately, there’s a good chance you’ll need to schedule an appointment with your PCP for follow-up testing.
If an at-home test isn’t an option for you, there are a couple of other colon cancer tests to consider, which include:
Standard colonoscopy. Most commonly used, this procedure uses a thin tube with a lens to examine the entire colon. Polyps or other tissues are also often removed for biopsy. Before a colonoscopy, your doctor will provide you with instructions that will help you clear out your colon as much as possible prior to testing. While the colonoscopy prep can take a few days, the test itself usually takes less than an hour. Luckily, improvements have been made to the preparation process, and a new colonoscopy prep tablet may make it easier for patients to prepare.
Virtual colonoscopy. Also known as computed tomography colonography (CTC), this test takes pictures of the colon through a series of x-rays or tomography, which produce digital images that show abnormalities. This test also requires colon cleansing in preparation. If polyps or other growths are found, a standard colonoscopy will be the next step to remove them. Further testing may also be needed if screening detects possible issues with surrounding organs, such as kidneys, liver, spleen, and pancreas.
Flexible sigmoidoscopy. In this procedure, a small tube-like instrument with a light and lens is used to look inside the rectum and lower (sigmoid) colon for polyps or other irregularities. Polyps or tissue samples may be removed and checked for signs of cancer. Sigmoidoscopy is less invasive and tends to take less time (about 15 – 20 minutes) than a standard colonoscopy. While it doesn’t generally doesn’t require an anesthetic, your doctor may provide you with a relaxant. Your doctor will tell you what you need to do to prepare.
Annual Screenings for Colon Cancer Can Save Your Life!
The colon cancer doctors at Compass Onco