Digital Rectal Exam

This procedure is often part of a routine physical examination. Your doctor will insert a finger into your rectum and feel for anything that is not normal, especially if you are experiencing bright red blood with bowel movements.

Colonoscopy

The doctor uses a colonoscope (narrow, flexible tube with a camera and light on the end) to examine the inner lining of your large intestine and remove any polyps before they can become malignant. Your doctor can also remove a tissue sample for biopsy during this procedure.

CT Colonography (Virtual Colonoscopy)

Your doctor uses a CT scanner to view the inside of your colon. This procedure is less invasive than a normal colonoscopy, but your doctor is not able to remove polyps or take biopsy samples. Therefore, a colonoscopy must still be completed.

Fecal Occult Blood Test (FOBT)

Your doctor performs this test to check for any signs of blood in the stool. Bloody stools are a symptom of colorectal cancer and may be caused by bleeding polyps or cancer inside the colon. Your doctor will collect a stool sample and send it to a lab to be analyzed with chemicals.

Fecal Immunochemical Test (FIT)

Your doctor may also order this test to find traces of blood in your stool. Your doctor collects a stool sample and sends it to a lab. The lab tests it for human hemoglobin, a protein in the blood. If there is hemoglobin in the stool, it means there are probably traces of blood in it.

Sigmoidoscopy

Your doctor uses a lighted tube called a sigmoidoscope to look at the inside of your rectum and lower colon and remove any polyps that are found. This test is similar to a colonoscopy, but does not examine the entire colon. It may be used more commonly for people who have a diagnosis of rectal cancer or sigmoid colon cancer.

Double-contrast barium enema

Your doctor gives you an enema of barium (a chalky, white liquid) and pumps air into your rectum. The barium coats the lining of the rectum and colon and clearly outlines them on X-rays. This makes it easier for your doctor to identify any polyps or tumors. This study can be limiting since it is very dependent on the mobility of the patient in getting the contrast to coat the bowel during the examination.

Stool DNA Test

A stool DNA test is used to detect DNA mutations in the stool that have been linked with colorectal cancer and colorectal polyps. The role of this test in colon cancer screening has yet to be defined. While the FDA has approved it for marketing and Medicare covers the test, the US Task Force on Prevention has not yet weighed in on whether they will add the test to their list of approved screening tests. For more information about this test, please discuss with your physician.

Endorectal ultrasound (rectal cancer only)

Your doctor will insert an ultrasound probe into your rectum. This device bounces sound waves off of your rectum in order to create echoes that form a picture. This allows doctors to see how deeply the tumor has grown and give an approximation if it has invaded the lymph nodes.

CEA Tumor Marker and Circulating tumor DNA testing (surveillance):

Tumor markers are substances that can be found in higher than normal amounts in a person's blood or urine when they have a specific type of cancer. The tumor marker for most colorectal cancers is carcinoembryonic antigen (CEA) and is elevated in 50-70% of all colorectal cancer patients.
Circulating tumor DNA testing (surveillance): Tumor cells shed their DNA into the bloodstream, and, even when microscopic levels of tumor cells might remain after curative-intent treatments, it is possible to detect mutations in the blood stream by looking for circulating tumor DNA (ctDNA). When ctDNA is detected there is a high likelihood for remaining cancer to be present. Alternatively, when ctDNA is not detected, it is less likely for the cancer to return. This test may be considered in surveillance after all standard therapies have been completed.

• Please see Understanding Tumor Markers: CEA for more information

Computed tomography (CT) scan

A computed tomography (CT) scan uses X-rays to produce an image of your body. A special dye may be injected into your veins and you may be asked to drink a special fluid in order to make the internal organs stand out. For a CT scan, you lie flat on a table while a machine rotates around your body and takes pictures. A CT scan reveals the presence of tumors and whether or not the cancer has spread to other parts of your body.

Magnetic resonance imaging (MRI) scan (more common for rectal cancer):

MRI scans use radio waves and a strong magnet to create clear and detailed images of the body. Radio waves are absorbed by the body and then released in a certain pattern, which is translated by a computer in order to show “slices” of the body. Doctors use MRIs to assess cancer spread and look at the brain and spinal cord. For patients with rectal cancer, MRI scans can provide important details about the tumor’s location and adjacent organs which it may contact.

Positron emission tomography (PET) scan:

A PET scan may be considered. For a PET scan, the doctor injects a radioactive substance into the patient's bloodstream. This substance collects in malignant (cancerous) cells in the patient's body. The doctor then uses a PET scanner to detect these areas of radioactivity and to find the exact location of cancer in the patient's body.

Circulating tumor DNA testing (surveillance):

Tumor cells shed their DNA into the bloodstream, and, even when microscopic levels of tumor cells might remain after curative-intent treatments, it is possible to detect mutations in the blood stream by looking for circulating tumor DNA (ctDNA). When ctDNA is detected, there is a high likelihood for remaining cancer to be present. Alternatively, when ctDNA is not detected, it is less likely for the cancer to return. This test may be considered in surveillance after all standard therapies have been completed.