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Colorectal cancer

Diagnosing colorectal cancer

A thorough and accurate cancer diagnosis is the first step in developing a colorectal cancer treatment plan. Your multidisciplinary team of colorectal cancer experts use a variety of tests and tools designed for diagnosing colorectal cancer, evaluating the disease and planning your individualized treatment. Throughout your treatment, we'll use imaging and laboratory tests to track the size of the tumors, monitor your response to treatment and modify your plan when needed.

Examples of procedures used for diagnosing colorectal cancer include:

Endoscopic procedures

Procedures such as a colonoscopy allow a doctor to examine the body from the inside. Doctors insert an endoscope or colonscope into the body to look for polyps or other abnormalities. In some cases, polyps may be removed during a colonoscopy.

Learn more about colonoscopies and other endoscopic procedures used to diagnose colorectal cancer

Lab tests

These tests include several stool tests that are conducted to look for blood, DNA abnormalities or other markers that may indicate cancer.

Learn more about lab tests used to diagnose colorectal cancer

Biopsies

These tests may be critical in helping diagnose colorectal cancer. A gastroenterologist performs a biopsy by retrieving polyps and other tissue samples from the colon or rectum during a colonoscopy. Tissue samples may also be retrieved during other endoscopic procedures, such as a sigmoidoscopy or endoscopic ultrasound. The polyps and samples are then sent to a laboratory to be analyzed under a microscope to check for cancer cells.

CT scan

Scans of the chest, abdomen and pelvis are performed to determine whether colorectal cancer has spread to other parts of the body, such as the lungs, liver or other organs. The scans also may help doctors stage the cancer. CT scans are typically performed before and at various points throughout colorectal cancer treatment, to help gauge whether treatment is working.

MRI

This imaging test may help doctors stage rectal cancer. MRIs use strong magnetic fields and radio waves to produce exceptionally detailed images. These tests also allow for greater soft-tissue contrast than a CT scan.

PET/CT scan

This test may be used to determine whether the colorectal cancer has spread to lymph nodes or other areas of the body, such as the liver or lungs. It also aids in staging the disease.

Ultrasound

This procedure may be used to produce images of internal organs from high-energy sound waves and echoes. Our doctors use ultrasound technology to check for tumors in abdominal organs, such as the liver, gallbladder and pancreas, especially if fluid has been found in the abdomen.

Barium enema

This test is used to take X-rays of the large intestine, which includes the colon and rectum. It helps doctors diagnose and stage colorectal cancer, and in some cases, it is used when a colonoscopy is not an option.

In this procedure, a doctor delivers an enema containing barium through a thin tube that is inserted through the rectum. The solution travels through the rectum and colon, coating the organs. Air is then released through the tube to help the colon expand and make it easier for your doctor to see abnormal growths. A series of X-rays are then taken to reveal images of the colon and rectum. These may enable the doctor to detect polyps and other suspicious tissues that need to be examined more closely or that should be removed during a colonoscopy.