How is Colorectal Cancer diagnosed?
In Singapore, diagnostic tests and imaging techniques are used to detect and diagnose colorectal cancer. These tests are essential for evaluating the presence of cancer, determining its stage, and guiding treatment decisions. Here are some common diagnostic tests and imaging techniques for colorectal cancer in Singapore:
Colonoscopy. Colonoscopy is considered the gold standard for diagnosing colorectal cancer. During the procedure, a flexible tube with a camera (colonoscope) is inserted into the rectum and guided through the entire colon. This allows for direct visualization of the colon lining, identification of any abnormalities such as polyps or tumors, and the ability to take biopsies for further analysis. Colonoscopy is typically performed under sedation or anesthesia for patient comfort.
Computed Tomography (CT) Colonography. CT colonography, also known as virtual colonoscopy, involves using a CT scanner to create detailed images of the colon and rectum. Prior to the procedure, air or carbon dioxide is pumped into the colon to help expand it for better visualization. The CT images are then examined for polyps or tumors that may indicate the presence of colorectal cancer. CT colonography is a non-invasive alternative to traditional colonoscopy, although a follow-up colonoscopy may be necessary if any abnormalities are detected.
Flexible Sigmoidoscopy. Flexible sigmoidoscopy focuses on examining the rectum and the lower part of the colon (sigmoid colon). It uses a flexible tube with a camera (sigmoidoscope) to visualize these areas and detect any abnormalities. While it doesn’t provide a complete view of the entire colon, it can be useful for evaluating the lower portion of the colon, where a significant number of colorectal cancers originate.
Barium Enema. A barium enema involves filling the colon with a contrast material (barium) through the rectum. X-rays are then taken to obtain images of the colon and rectum, which can reveal any abnormalities. While this technique has been largely replaced by colonoscopy and CT colonography, it may still be used in specific cases or when other options are not feasible.
Magnetic Resonance Imaging (MRI). MRI utilizes magnetic fields and radio waves to create detailed images of the colon and rectum. It can provide information about the extent of the tumor, including its size, location, and involvement of nearby structures. MRI is particularly helpful in assessing the depth of tumor invasion and determining if the cancer has spread to surrounding lymph nodes.
Positron Emission Tomography (PET) Scan. PET scans involve the injection of a small amount of radioactive material, known as a tracer, into the bloodstream. Cancer cells absorb more of the tracer than normal cells, making them visible during the scan. PET scans can help determine the spread of cancer beyond the colon and identify distant metastases in other organs.
Blood Tests. Blood tests, such as the carcinoembryonic antigen (CEA) test, may be performed to measure certain tumor markers in the blood. Elevated levels of CEA or other markers associated with colorectal cancer can indicate the presence of the disease or monitor treatment response.
The choice of diagnostic tests and imaging techniques depends on various factors, including the patient’s specific situation, symptoms, and the recommendations of healthcare professionals in Singapore. They work collaboratively to determine the most appropriate diagnostic approach for each individual.
