What is the gold standard diagnostic procedure for colorectal cancer?

The gold standard diagnostic procedure for colorectal cancer is colonoscopy with biopsy. This method allows for direct visualization of the colon and rectum, enabling the identification of abnormal growths or lesions. If suspicious lesions are found, a biopsy can be performed during the colonoscopy, which involves taking a tissue sample that can then be analyzed histologically for cancerous cells. This combination of direct visualization and histological confirmation is crucial for an accurate diagnosis.

Other methods, while useful, do not provide the same level of definitive diagnosis. A CT scan of the abdomen can help in staging cancer after diagnosis but does not confirm the presence of cancer itself. The fecal occult blood test is a screening tool that detects hidden blood in the stool, which can indicate potential issues but does not provide a definitive diagnosis. Lastly, a colonoscopy without biopsy allows for visualization but lacks the confirmatory tissue analysis needed to diagnose cancer definitively. Therefore, colonoscopy with biopsy remains the most reliable procedure for diagnosing colorectal cancer.