What is Colorectal cancer?
Colorectal cancer also referred to as CRC, is cancer that starts somewhere inside the colon or rectum of the digestive system. It is the third most common cancer in the United States for both men and women, and although rates of CRC overall have been decreasing, the rates have actually been going up for younger adults.
CRC starts off by abnormal cells developing in the colon or rectum. These often start out by becoming polyps, small growths of tissue along the intestinal wall. Not all polyps will become cancer, and if they do, it can take many years for them to develop into cancer.
Signs and Symptoms
Someone may have colon cancer and not have any signs or symptoms of it being there. This is what makes screening tests so important, so cancer can be caught before it becomes advanced. If someone does have symptoms, they may include:
- Changes in bowel patterns (such as diarrhea or constipation)
- Fatigue
- Unintentional weight loss
- Blood in the stool, or dark or tarry stool
- Abdominal pain
Diagnostic Tests
If someone is having symptoms that may be concerning for CRC, a stool sample can be obtained to check for blood in the stool that might not be visible to the naked eye. If this test is positive, it’s likely a colonoscopy will be ordered.
Not only are colonoscopies suggested if blood is present in the stool, but it may also be recommended to be done as a screening tool to detect colon cancer early. During this procedure, a special camera is inserted into the rectum and moved up into the large intestine to evaluate the lining and look for any abnormalities. If a polyp or any area of abnormality is found, it can be biopsied and tested for cancer cells. A colonoscopy requires a day or so of preparation, where no solid foods are eaten, only clear liquids are to be consumed, and large amounts of laxatives are used to clean out the colon. This prep allows the gastroenterologist performing the procedure to get the best look possible at the intestinal wall.
Once a diagnosis of CRC is made, the oncologist will likely order additional tests to learn the characteristics of the cancer. This can include molecular testing to see if there are any mutations present, such as BRAF, NRAS, or KRAS. Knowing if these mutations are present can help the oncologist come up with a treatment plan.
Additional testing, such as CT scans or PET scans may also be done to determine if CRC has spread to any other areas of your body. Once all of the testing is complete, your oncologist can stage the cancer.
Are you interested in learning more about colorectal cancer staging? Check out our next article on this topic.
