A diagnosis of cancer will likely start with a visit to your primary care physician, who will obtain a thorough medical history and then perform a physical examination.
In addition to the history and physical, he or she will then utilize any of the following tools to arrive at a diagnosis:
A CT scan also uses x-rays to generate an image, but it has several advantages compared to the chest x-ray. It will show the precise location, shape, and size of masses. In order to obtain even sharper images, some patients are asked to drink or receive IV contrast. This contrast makes some tissues appear brighter, which makes the images and the structures more apparent and easier to discern. Allergies to contrast medium may cause hives, flushing, shortness of breath, and low blood pressure. If you have had a reaction to contrast before, you should inform your physician. In addition to masses (such as cancers), it can show enlarged lymph nodes, which may have cancer cells. Many patients will have CT scans of the chest, abdomen, brain, and extremities. A CT scan may also be used to obtain biopsies of masses or cancers what lie deep within or nearby other vital structures, which is termed CT guided needle biopsy.
A magnetic resonance imaging (MRI) study also provides detailed soft tissue “pictures.” As opposed to CT scans, which utilizes x-rays, MRIs use magnetic radio waves to generate images. MRIs are particularly useful for imaging the brain and spinal cord. Gadolinium, a contrast, is often used to produce even better MRI images. A specific MRI scan called an MRA uses contrast to assess blood vessels, which may be supplying nutrients to the cancerous tissue.
Ultrasound imaging may also prove useful in the diagnostic process. By utilizing sound waves, ultrasound generates images of the organs. To take a sonogram, your doctor or sonographer will place a transducer on the abdomen and evaluate the image on the screen. There is no radiation with ultrasound imaging.
PET scans, also known as positron emission tomography, are especially useful to look for cancer spread. This study involves injecting a special radioactive sugar (flourodeoxyglucose, or FDP) into the vein. The amount of radioactivity is very low and will not cause you harm. After the injection, a special scanner will pick up areas in your body where the sugar has accumulated. As cancer cells are very active and require a great amount of energy (sugar), the FDP will concentrate in these areas. The PET scan does not produce extremely detailed images, but rather indicates spread of cancer throughout the body.
Bone scans can also be performed to detect spread of cancer to bones. During this procedure, a radioactive dye is injected in the vein, where is it transported to areas of bone with abundant activity, which may occur in cancerous and non-cancerous states.
A simple chest x-ray or radiograph will usually be taken, as it is convenient, cheap, and will reveal if the cancer has progressed to the lungs.
Angiography, which utilizes a specialized intravenous dye to visualize the arteries of the body, may also be used to help demonstrate the blood supply of the tumor and to help the surgeon plan his or her surgery.
If a suspicious mass is identified via the aforementioned tests, a biopsy may need to be performed to ensure proper diagnosis. During a biopsy, a small amount of tissue is removed from the suspicious mass and then assessed under the microscope. A biopsy is commonly performed as a fine needle aspiration, or FNA, which utilizes CT imaging and a long, thin needle to pierce the skin and to obtain a small tissue sample of the mass. A pathologist will then study the biopsy to determine if the mass is benign or malignant and will then identify the exact type of malignancy.
Possible lab tests used to help diagnose cancers include a complete blood count (CBC), basic metabolic panel (BMP), liver enzymes, and substances in blood known as tumor markers, which include CA19-9, CA-125, and carcinoembryonic antigen (CEA).