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Doctors use many tests to diagnose cancer and find out if it has metastasized. Some tests may also determine which treatments may be the most effective. For most types of cancer, 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
- Type of cancer suspected
- Severity of symptoms
- Previous test results
If a doctor suspects that a person has pancreatic cancer, he or she will first ask about the person's medical history and examine the person to look for signs of the disease. An appropriate and timely diagnosis is very important, ideally performed at a center that has experience with the disease. The tests listed below may be used to diagnose pancreatic cancer.
Physical examination. The doctor will examine the skin and eyes to see if they are yellow, which is a sign of jaundice. Jaundice can be from a tumor in the head of the pancreas blocking the normal flow of bile (a substance produced in the liver) into the small intestine. However, many patients with pancreatic cancer do not have jaundice when the cancer is diagnosed. The doctor will also feel the abdomen for changes caused by the cancer, although the pancreas itself, located in the back of the upper abdomen, can rarely be felt. An abnormal buildup of fluid in the abdomen, called ascites, may be another sign of cancer.
Blood tests. The doctor may take samples of blood to check for abnormal levels of bilirubin and other substances. Bilirubin is a chemical that may reach high levels in patients with pancreatic cancer due to blockage of the common bile duct by a tumor. There are many other non-cancerous causes of an elevated bilirubin level, such as hepatitis, gallstones, or mononucleosis. CA 19-9 is a tumor marker (substance in the body that may be found at higher levels if cancer is present) that can be measured in the blood, and is often higher in people with pancreatic cancer. High levels of CA 19-9 should not be used as the only test to make the diagnosis of pancreatic cancer, as high levels of CA 19-9 also can be a sign of other, noncancerous conditions, such as pancreatitis, cirrhosis of the liver, and blockage of the common bile duct.
Imaging tests help doctors find out where the cancer is located and whether it has spread from the pancreas to other parts of the body. Pancreatic cancer often does not develop as a single large tumor, which means it can sometimes be difficult to see on imaging tests. However, newer computed tomography scanners (see below) produce better, clearer images that can be easier to interpret. A radiologist is a doctor who specializes in interpreting imaging tests.
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 contrast medium (a special dye) is usually injected into a patient’s vein to provide better detail. Many cancer centers use a special type of CT scan called a pancreatic protocol CT scan. This scan focuses specifically on the pancreas using different levels of detail to make clearer images. It is used to find out exactly where the tumor is in comparison to nearby organs and vessels and help decide if the tumor could be removed with surgery.
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. This substance is absorbed mainly by organs and tissues that use the most energy. Because cancer tends to use energy actively, it absorbs more of the radioactive substance. A scanner then detects this substance to produce images of the inside of the body. A PET scan is often done in combination with a CT scan, with the images placed over each other (called a fusion or integrated CT-PET scan). PET scans are done regularly at some but not all cancer centers for the diagnosis and staging of pancreatic cancer. However, they are not yet considered a standard test to diagnose pancreatic cancer. A PET scan alone should never be used instead of a high-quality CT scan.
Ultrasound. An ultrasound uses sound waves to create a picture of the internal organs. There are two types of ultrasound devices: transabdominal and endoscopic.
- A transabdominal ultrasound device is placed on the outside of the abdomen and is slowly moved around by the doctor to produce an image of the pancreas and surrounding structures.
- The endoscopic ultrasound (EUS) device is a thin, lighted tube that is passed through the patient's mouth and stomach and down into the small intestine to take a picture of the pancreas. This procedure is very specialized and requires a gastroenterologist (a doctor who specializes in the function and disorders of the gastrointestinal tract, including stomach, intestines, and similar organs) who has special training in this area. It is generally done under sedation, so the patient sleeps through the procedure.
Endoscopic retrograde cholangiopancreatography (ERCP). In this procedure performed by a gastroenterologist, an endoscope (a thin, lighted tube) is passed into the small intestine through the mouth and stomach. A catheter (smaller tube) is passed through the endoscope and into the bile ducts and pancreatic ducts. Dye is injected into the ducts, and the doctor then takes x-rays that can show whether a duct is compressed or narrowed. Often, a plastic or metal stent can be placed across the obstructed bile duct during ERCP to help relieve any jaundice. Samples of the tissue can be taken during this procedure and can sometimes help confirm the diagnosis of cancer. The patient is lightly sedated during this procedure.
Percutaneous transhepatic cholangiography (PTC). In this x-ray procedure, a thin needle is inserted through the skin and into the liver. A dye is injected through the needle, so the bile ducts show up on x-rays. By looking at the x-rays, the doctor can tell whether there is a blockage of the bile ducts.
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).
One biopsy technique used to remove pancreas tissue is called fine needle aspiration, in which a needle is inserted into the pancreas to suction out cells. An x-ray or CT-guided ultrasound is used to help direct the needle to the correct place. Other ways to collect a sample of pancreas tissue involve the use of ERCP, EUS, or surgery. If the cancer has spread to other organs, a biopsy may be needed from one of these other sites (such as the liver). A surgical biopsy can be done either by opening the abdomen or by using a laparoscopic approach to provide openings for a tiny camera and surgical instruments, which requires much smaller incisions. Learn more about different biopsy techniques.
Molecular testing of the tumor. Your doctor may recommend running laboratory tests on a tumor sample to identify specific genes, proteins, and other factors unique to the tumor (called biomarkers). Examples of biomarkers for pancreatic cancer include KRAS, SPARC, hENT1, and DPC4. Some patients, when having surgery or certain types of biopsies (see above), choose to have some of the tissue removed frozen and sent to independent laboratories that look at some or all of these biomarkers. Results of these tests may help to guide treatment decisions, although more research is needed for this to become a standard way of making treatment decisions. However, it is an area of increasing interest and scientific focus. It is important to note that many insurance companies do not reimburse for these types of tests yet. Talk with your doctor for more information.
Learn more about what to expect when having common tests, procedures, and scans.
After these diagnostic tests are done, your doctor will review all of the results with you. If the diagnosis is cancer, these results also help the doctor describe the cancer; this is called staging. Learn more about the first steps to take after a diagnosis of cancer.