Colon cancer is the development of cancer in the colon, or large intestine. It generally begins as small, noncancerous lumps, known as adenomatous polyps, that are asymptomatic and can take some time to turn into full-blown cancerous cells.
This is largely the reason yearly colon cancer screenings are recommended—the sooner this type of cancer is detected, the more fully it can be treated. Whether through annual screenings or because of suspicious symptoms, more than one manner of diagnosis is available. Here is a look at how colon cancer is diagnosed and staged.
Annual screenings for colon cancer should generally begin around age 50. However, people with a family history or other risk factors may need to begin screening earlier. According to the American Society of Clinical Oncology, a colorectal screening may consist of a colonoscopy, sigmoidoscopy, computerized tomography (CT or CAT) scan, fecal occult blood test (FOBT), double contrast barium enema, or DNA tests from fecal matter. The ultimate goal of these screenings is to determine if any polyps are present, so they can be removed quickly before they turn cancerous.
If your doctor suspects your symptoms may be caused by colon cancer, any of the tests used for screening may be utilized to actually diagnose the condition as well, along with a few additional options.
A small tube with a camera and light attached are inserted through the rectum of the sedated patient. A colonoscopy also allows the doctor to take biopsies, or small samples of tissue, remove possible pre-cancerous polyps, all whilst examining the entirety of the large intestine.
A sigmoidoscopy is very similar to a colonoscopy, but only allows the lower part of the colon to be viewed. It can be used to determine if a full colonoscopy is necessary.
- CT Scan:
Using x-ray technology mixed with computer abilities, a CT scan provides a real-time video of the colon. It is generally used as an alternative for patients who are not good candidates for a colonoscopy.
- Blood Tests:
A fecal occult blood test examines stool for blood, which can be indicative of the development of polyps, etc. Among other types of specific testing, a complete blood count (CBC) may be used to check the levels of red blood cells for normalcy.
- Double Contrast Barium Enema:
Another alternative for patients who cannot undergo a colonoscopy is to receive an enema containing barium, which highlights the intestines. However, it tends to be less accurate for diagnosis.
- DNA Test:
Using the patient’s stool, DNA may be extracted and examined for any changes that might indicate the presence of cancer.
- Additional imaging tests (such as an ultrasound or positron emission tomography scan) may be used to detect exactly where the cancer is located within the colon and the extent to which it may have spread to other tissues and organs in the body. If you are over 50 and have never had a colon screening or have been exhibiting symptoms typical of colorectal cancers, see a doctor immediately about your concerns.