Doctors use many tests to diagnose a tumor and determine if it if is cancerous and, if so, 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
In addition to a physical examination, the following tests may be used to diagnose an endocrine tumor:
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). There are many types of biopsies. The type of biopsy performed will depend on the location of the tumor. Two of the more common types of biopsies used in the diagnosis of an endocrine tumor are:
- Fine needle aspiration. This procedure is usually performed in a doctor’s office or clinic. A local anesthetic may be injected into the skin near the tumor before the biopsy to numb the area. The doctor inserts a thin needle into the tumor and removes cells and some fluid. The procedure may be repeated two or three times to obtain samples from different areas of the tumor. The report done by the pathologist can be positive (meaning there are cancerous cells), negative (meaning there are no cancerous cells), or undetermined.
- Surgical biopsy. If the needle aspiration biopsy is not conclusive, the doctor may suggest a biopsy in which the tumor and possibly other tissues in the area will be removed by surgery. This procedure is most often done under general anesthesia and on an outpatient basis.
Laboratory tests. The doctor may need samples of the patient’s blood, urine, and stool to check for abnormal levels of hormones, glucose levels, and other substances.
Neurological examination. An evaluation of the central nervous system may include testing of the reflexes, motor and sensory skills, balance and coordination, and mental status.
Imaging tests
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.
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. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail.
Endoscopy. This test allows the doctor to see inside the body 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.
A colonoscope is a type of endoscope that is inserted through the anus into the colon. It can be used to diagnose a tumor in the lower section of the digestive system.
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.
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. Because some endocrine tumors grow very slowly, a PET scan may not be helpful in diagnosis.
Radionuclide scanning (OctreoScan). A small amount of a radioactive hormone-like substance is injected into a vein. A special camera is then used to show where the radioactivity accumulates. This procedure is useful in detecting the spread of an endocrine tumor, especially to the liver. The test takes place over the course of multiple days.
X-ray. An x-ray is a picture of the inside of the body. For instance, a chest x-ray can help doctors determine if the cancer has spread to the lungs.
Learn more about what to expect when having common tests, procedures, and scans.
Find out more about common terms used during a diagnosis of cancer.
