Lung Cancer Diagnosis

As the leading cause of cancer death in the United States, being diagnosed with lung cancer can seem overwhelming. This is especially true for those diagnosed with asbestos-induced lung cancer, as their exposure likely occurred decades before symptoms began to arise. Asbestos can cause all major types of lung cancer, and when combined with smoking, the risk greatly increases (by as much as 84 or more times).

Though the symptoms of lung cancer can vary depending on the type and location of the cancer, the diagnostic tools and procedures involved are essentially the same. Those who exhibit symptoms of lung cancer must contact their physician or oncologist for a physical exam and an analysis of medical history. The doctor will review and evaluate the patient's symptoms and risk factors, and if lung cancer is suspected, more tests will follow. These may include a variety of imaging tests and/or biopsies of lung tissue that are known to help diagnose lung cancer.

Imaging Tests

These types of tests employ the use of x-rays, magnetic fields, or radioactive substances to create images of internal parts of the body. Imaging tests are performed for a variety of reasons, such as to produce a picture of a potentially cancerous area, to see if the cancer has spread, and to determine if treatment efforts are producing effective results. The following imaging tests may be used to diagnose various types of lung cancer:

• Chest X-ray - An x-ray of the chest is traditionally the first test a doctor orders when diagnosing lung cancer. If anything suspicious is detected in the x-ray, further tests will likely be ordered.
• Computed Tomography (CT) Scan - A CT scan, also known as a CAT scan, is an x-ray test that creates cross-sectional images of the body. While a patient lies in a stationary position, a CT scanner rotates around the patient and takes a multitude of pictures. A computer combines the pictures to produce images of the insides of the patient's body, which, unlike an x-ray, creates more detailed images of soft tissue. A contrast solution may also be used to create another set of images.
• Magnetic Resonance Imaging (MRI) Scan - MRI scans employ the use of radio waves and strong magnets as opposed to x-rays, but like a CT scan, detailed images of soft tissue are produced.
• Positron Emission Tomography (PET) Scan - These scans begin with an injection of glucose that contains a radioactive atom. Though very low radioactivity is used, cancerous cells absorb large amounts of the radioactive sugar, which allows an image to be produced by the scan that reveals areas of radioactivity. The image is not detailed like that of a CT or MRI scan, but can provide vital information about the entire body.
• Bone Scan - A bone scan can be used to detect whether or not cancer has spread to the bones. A radioactive material is injected intravenously, which then settles in damaged bone areas throughout the body. A special camera that detects the radioactivity is then used to take pictures of a patient's skeleton.

Tissue Sampling

The diagnosis of lung cancer is typically carried out by examining lung cells through a microscope. These cells can be gathered by extracting them from the suspicious area, or from lung secretions such as phlegm. Determining the type of lung cancer that is present and discovering if the disease has spread can be done through the following tests:

• Sputum Cytology - In this test, a sample of phlegm is observed and examined under a microscope for the presence of cancer cells.
• Fine Needle Aspiration (FNA) Biopsy - Using a hollow needle, a sample of tissue is extracted from a suspicious area inside the body. The sample is then examined under a microscope to see if cancerous cells are observable.
• Bronchoscopy - To begin this procedure, the mouth and throat are first sprayed with a numbing agent. Then a lighted, flexible tube called a bronchoscope is place in the mouth and down into the windpipe and bronchi. This test can help discover tumors or blockages in the lungs while allowing small instruments to be placed down the bronchoscope to collect samples of tissue or lung secretions.
• Endobronchial Ultrasound - A bronchoscope is passed down the windpipe with an ultrasound transducer attached at the tip. The transducer can be pointed in multiple directions to observe structures in the lungs. When a suspicious area is observed in the ultrasound, a hollow needle can then be passed down the bronchoscope to collect tissue samples.
• Endoscopic Esophageal Ultrasound (EUS) - This procedure is very similar to an endobronchial ultrasound, but an endoscope is placed down the throat and into the esophagus (which is behind the windpipe) instead of a bronchoscope into the windpipe. Since the esophagus is close to certain lymph nodes in the chest, this procedure can help to identify lymph nodes that may contain cancerous cells. A hollow needle can also be passed down the endoscope to collect a biopsy (tissue sample) for testing.
• Mediastinoscopy and Mediastinotomy - Both of these techniques allow medical professionals to observe more directly and sample questionable structures in the area between the lungs, which is known as the mediastinum. These procedures are performed in an operating room while the patient is under general anesthesia. A mediastinoscopy involves a small incision being made in the front portion of the neck above the breastbone, through which a hollow, lighted tube is inserted to observe the major bronchial tube areas. The difference in a mediastinotomy is a slightly larger incision is made between the second and third ribs near the beast bone, which allows the doctor to reach lymph nodes that are not accessible through a mediastinoscopy.
• Thoracentesis - This procedure is performed to determine whether an accumulation of fluid around the lungs, which is known as pleural effusion, is caused by the spread of cancer into the lining of the lungs (pleura). During the procedure, a needle is placed between the ribs to drain the collected fluid. This fluid is then examined under a microscope for the presence of cancer.
• Thoracoscopy - To decipher if cancer has spread to the space between the lungs and chest wall (as well as the lining of these areas), a lighted tube with a video camera attached to the end is passed through a small incision in the chest wall. This allows doctors to view potential cancerous areas as well as sample tissue to be observed under a microscope.

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