Carcinoid Tumors Diagnosis
Doctors use many tests to diagnose a tumor and determine if it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most types of tumors, a biopsy is the only way to make a definitive diagnosis of cancer. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether the cancer has metastasized. Your doctor may consider these factors when choosing a diagnostic test:
- Age and medical condition
- The type of cancer suspected
- Severity of symptoms
- Previous test results
Most carcinoid tumors are found unexpectedly when people are having x-rays or medical procedures done unrelated to the tumor. For example, many carcinoid tumors of the appendix are found during appendectomies (surgery to remove the appendix); duodenal (the top of the small intestine) and stomach carcinoid tumors are usually found during endoscopies.
If a doctor suspects a carcinoid tumor is present, he or she will obtain a complete medical and family history. The doctor will also perform a thorough physical examination and may conduct other tests.
In addition to a physical examination, the following tests may be used to diagnose a carcinoid tumor:
Laboratory tests. The doctor may need samples of the patient’s blood and urine to check for abnormal levels of hormones and other substances. Urine tests check the measurement of 5-HIAA. Measurements for serotonin levels may also be taken. A doctor may be able to diagnose a carcinoid tumor from a urine test alone. A blood test to measure chromogranin-A may be needed, since the serum serotonin level fluctuates and may not be as useful as a chromogranin-A test.
Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The sample removed from the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease).
Upper endoscopy. This test allows the doctor to see the lining of the upper digestive system with a thin, lighted, flexible tube called an endoscope. The person may be sedated as the tube is inserted through the mouth, down the esophagus, and into the stomach and small bowel. If an abnormality is found, a biopsy will be performed.
A colonoscope is a type of endoscope that is inserted through the anus into the colon. It can be used to diagnose tumors in the lower section of the digestive system.
Endoscopic ultrasound. An ultrasound uses sound waves to create a picture of the internal organs. This procedure is often done at the same time as the upper endoscopy. In an endoscopic ultrasound, a transducer (a machine that produces the sound waves) is inserted into the upper digestive tract through the mouth. The endoscopic ultrasound can show enlarged lymph nodes, which may indicate a tumor or advanced disease.
Bone scan. A bone scan uses a radioactive tracer to look at the inside of the bones. The tracer is injected into a patient’s vein. It collects in areas of the bone and is detected by a special camera. Healthy bone appears gray to the camera, and areas of injury, such as those caused by cancer, appear dark.
X-ray An x-ray is a picture of the inside of the body. For instance, a chest x-ray may be taken to look for a carcinoid tumor in the lungs. Some carcinoid tumors may not show up on a chest x-ray due to their size or location, so the doctor may also order a computed tomography (CT or CAT) scan.
Barium x-rays. In a barium swallow, a person swallows a liquid containing barium and then a series of x-rays are taken. The barium coats the lining of the esophagus, stomach, and intestines, so abnormalities are easier to see on the x-ray. If there is an abnormality, an endoscopy biopsy can help make the diagnosis of cancer.
A barium enema may be given before x-rays are taken to show the inner surface of the large intestine. During this test, a barium solution is given through the anus and flows throughout the colon, then the x-rays are taken.
Computed tomography (CT or CAT) scan. A CT scan creates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. A CT scan is used to see if the tumor has spread to the liver and to detect a carcinoid tumor in the retroperitoneal (the area behind the abdomen) lymph nodes. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail.
Magnetic resonance imaging (MRI). An MRI uses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium may be injected into a patient’s vein to create a clearer picture.
Radionuclide scanning (OctreoScan). A small amount of a radioactive hormone-like substance that is attracted to carcinoid tumors is injected into a patient’s vein. A special camera is then used to show where the radioactivity accumulates. This procedure is useful in detecting spread of a carcinoid tumor, especially to the liver.
Positron emission tomography (PET) scan. A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into a patient’s body and absorbed by the organs or tissues being studied. This substance gives off energy that is detected by a scanner, which produces the images. However, because carcinoid tumors grow very slowly, a PET scan may not be as helpful as other tests in diagnosis.
