Your doctor may use one or more approaches to diagnose cancer:
- Physical exam. Your doctor may feel areas of your body for lumps that may indicate a tumor. During a physical exam he or she may look for any abnormalities, such as changes in skin color or enlargement of an organ, that may indicate cancer.
- Laboratory tests. Laboratory tests, such as urine and blood tests, may help your doctor identify abnormalities that can be caused by cancer. For instance, in people with leukemia, a common blood test called complete blood count (CBC) may reveal an unusual number of white blood cells.
- Imaging tests. Imaging tests allow your doctor to examine your bones and internal organs in a noninvasive way. Imaging tests used in diagnosing cancer may include computerized tomography (CT) scan, bone scan, magnetic resonance imaging (MRI), ultrasound and X-ray, among others.
While imaging tests, such as X-rays, are helpful in detecting masses or areas of abnormality, they alone can't differentiate cancerous cells from noncancerous cells. For the majority of cancers, the only way to make a definitive diagnosis is to use a biopsy to collect cells for closer examination.
- Biopsy. During a biopsy, your doctor collects a sample of cells for testing in the laboratory. There are several different ways of collecting a biopsy sample. Which biopsy procedure is right for you depends on your type of cancer and its location. Some of the most common kinds of biopsies are:
- Bone marrow biopsy - This type of biopsy is done if laboratory tests indicate an abnormality in the blood. Problems in the blood can be due to both non-cancerous conditions as well as cancer including leukemia, lymphoma and multiple myeloma. Since blood cells are produced in the marrow of bones, looking at the cells in the bone marrow is an effective way to determine the cause of the abnormality in the blood. After an anesthetic is injected into the site of the biopsy to help minimize pain and discomfort, the physician inserts a long needle into a bone most often the back of one of the hip bones and removes a sample of the bone marrow. This procedure is often performed in the doctor's office.
- Endoscopic biopsy - An endoscope is a thin, tube-like instrument with a light and a lens for viewing. In an endoscopic biopsy, special tools are passed through the tube to remove tissue to be checked under a microscope for signs of disease. Examples of endoscopic biopsy procedures include cytoscopy to collect tissue from the inside of your bladder, bronchoscopy to get tissue from inside your lung and colonoscopy to collect tissue from inside your colon. This procedure can be performed in a doctor's office, in an outpatient surgical center or at the hospital. You may receive anesthesia and/or a sedative before the procedure.
- Needle biopsy - In this type of biopsy, a needle is used to remove tissue or fluid with a needle for examination under a microscope. There are several types of needle biopsies:
- Core needle biopsy - a wide needle with a special cutting tip is used to draw a sample of cells from the suspicious area.
- Fine needle aspiration - a long, thin needle attached to a syringes is inserted into the suspicious area and used to draw out a sample of cells or fluid.
- Vacuum-assisted biopsy - procedure in which a small sample of tissue is removed with the assistance of a gentle vacuum. An imaging device is used to guide a hollow probe connected to a vacuum device. The probe is inserted through a tiny cut made in numbed skin on the breast. The tissue sample is removed using gentle vacuum suction and a small rotating knife within the probe. This procedure causes very little scarring and no stitches are needed. Also called VACB and vacuum-assisted core biopsy.
- Image-guided biopsy. Image-guided biopsy combines an imaging procedure, such as X-ray, computerized tomography (CT) or ultrasound, with a needle biopsy. Image-guided biopsy allows your doctor to access suspicious areas that can't be felt through the skin, such as abnormalities on the liver, lung or prostate. Using real-time images, your doctor can make sure the needle reaches the correct spot.
Regardless of the type of biopsy performed, the cells or tissue obtained is sent to the Pathology Department a special section within the laboratory. There, specially trained physicians, called Pathologists, look at biopsy samples under the microscope. Normal cells look uniform, with similar sizes and orderly organization. Cancer cells look less orderly, with varying sizes and without apparent organization. Pathologists use a variety of special chemical stains and other tests to pin point the exact type of cancer cells. This is a critical step as different cancer cells require different treatment approaches.
For additional information on tests used to diagnose cancer, please click here to go to the National Cancer Institute's (NCI) website.