How are colon cancer patients primarily investigated who meet the referral criteria?

The primary investigation for colon cancer patients who meet the referral criteria is through colonoscopy and CT cologram. Colonoscopy is considered the gold standard for investigating suspected colorectal pathology, as it allows direct visualization of the colon, the ability to perform biopsies, and the removal of polyps during the procedure. This makes it an essential tool in both diagnosis and potential management of colorectal cancer.

A CT cologram, also known as a CT colonography or virtual colonoscopy, is a non-invasive imaging technique that can be used as an adjunct to colonoscopy. It provides detailed images of the colon and can help in identifying abnormalities when colonoscopy is either not feasible or in cases of incomplete examinations.

While a physical examination and blood tests may provide initial general health information, they are not specific or comprehensive enough to diagnose colon cancer. Similarly, the digital rectal exam, MRI, ultrasound, and sigmoidoscopy do not offer the same level of thorough investigation as colonoscopy and CT cologram when it comes to colorectal cancer evaluation. Therefore, the combination of colonoscopy and CT cologram is deemed the most effective investigative approach for patients suspected of having colon cancer.