Is a CT scan of the colon as good as a colonoscopy?
A traditional colonoscopy is the most widely known colorectal cancer screening procedure, but many patients are choosing a non-invasive CT (computerized tomography) Colonography instead. A CT Colonography doesn't require sedation and is just as accurate at detecting most precancerous polyps.
One test can prevent cancer.
Colonoscopy offers the only way to find and remove polyps in one exam. That means your doctor can remove abnormal growths before they turn into cancer. At-home stool tests cannot prevent colon cancer. They are considered colon cancer detection tests, which means cancer has already formed.
A colonoscopy is not your only option for screening for colon cancer. Other screening methods are sigmoidoscopy, virtual colonoscopy, a fecal immunochemical test, a fecal occult blood test, or a stool DNA test.
Despite the development of other screening methods, colonoscopy remains the gold standard for colon cancer detection. Research indicates that colonoscopies—regardless of whether they are performed in the hospital or at an outpatient facility—yield up to 94 percent accuracy rate.
Virtual colonoscopy is also known as screening CT colonography. Unlike traditional colonoscopy, which requires a scope to be inserted into your rectum and advanced through your colon, virtual colonoscopy uses a CT scan to produce hundreds of cross-sectional images of your abdominal organs.
What Are the Main Differences Between a CT Scan and Colonoscopy? CT scans utilize X-rays to form images of organs and tissues inside the body (for example, abdominal organs, brain, chest, lungs, heart) while colonoscopy is a procedure that can visualize only the inside surface of the colon.
Home, stool-based tests can be part of a screening program — but should never replace colonoscopy, the 'gold standard' of colorectal cancer prevention. Colorectal cancer is one of the most treatable forms of cancer.
Stool DNA testing is used to screen for colon cancer in people with no symptoms. It also screens for growths of cells, called polyps, that could one day become cancer. The stool DNA test looks for DNA changes and small amounts of blood shed into the stool. These might come from colon cancer or colon polyps.
Accuracy – Colonoscopy detects over 95% of all colorectal cancers, while Cologuard detects 92% of colorectal cancers and only 42% of the precancerous polyps (the large and advanced type). Both doctor and patient must bear in mind that Cologuard has a 13% false-positive rate.
...
Table 3.
| Finding | Frequency |
|---|---|
| True positive | 2 |
| True negative | 90 |
| False positive | 4 |
| False negative | 0 |
Is a CT scan with contrast better than a colonoscopy?
CT colonography has a much lower risk of perforating the colon than conventional colonoscopy. Most people who undergo CT colonography do not have polyps and can be spared having to undergo a full colonoscopy which typically requires sedation.
In a number of studies, CT colonography has displayed results equivalent to colonoscopy in both cancer and polyp detection. CT colonography has been shown to rapidly and effectively examine the entire colon for lesions.
A CT scan uses x-rays to make detailed cross-sectional images of your body. This test can help tell if colorectal cancer has spread to nearby lymph nodes or to your liver, lungs, or other organs.