An estimated 1.9 million people around the world are diagnosed with colorectal cancer every year, according to the World Health Organization.
Many in the early stages of the disease show no symptoms, noted Owens, an associate medical director at Quest Diagnostics, a clinical lab in Marlborough, Massachusetts, that provides cancer screening tests.
But one early warning sign that a patient may develop colon cancer is the presence of sessile serrated adenomas, or SSAs, in their tissue. SSAs are precancerous lesions found in the inner lining of the colon. However, these lesions can be hard to detect in certain cases because they are hard to spot on biopsy slides, Owens said.