The National Cancer Institute's definition of screening for cancer is the examination or testing of people for early signs of certain type of cancer even though they have no symptons - this is the best way to achieve a diagnosis as early as possible. Early detection and diagnosis is particularly important for people with historical exposure to asbestos due to the latency period (up to 30 years) before which symptoms of malignant mesothelioma cancer may become apparent.
Early Signs of Mesothelioma Aid Diagnosis:
Recognizing early symptoms of malignant mesothelioma may aid in diagnosis. Symptoms include difficulty in breathing (dyspnea) and/or chest pains, fever, nausea or anemia; other signals are hoarseness, difficulty swallowing (dysphagia), or coughing up blood (hemoptysis). For many suffering from pleural mesothelioma, there may be pain in the chest or lower back. Those people with peritoneal mesothelioma may experience an expanding waist size or abdominal pain resulting from the growth of cancer cells in the abdomen.
Since many of these symptoms are also caused by less serious illnesses, it can be difficult to recognize asbestos-related diseases in the early stages. Due to this difficulty of early diagnosis of asbestos cancer and mesothelioma, the best way to determine your health risk is to consult a doctor for an initial examination, which may include a pulmonary function test (PFT) and x-rays.
Screening Methods to Identify Asbestos-Related Disease:
After a preliminary physical examination, the doctor may need to look inside your chest cavity with a thorascope for accurate diagnosis. During this thoracoscopy procedure, a cut will be made in your chest and a small piece of tissue (biopsy) may removed for examination. While you may feel some pressure, there is usually no pain.
Another special tool that may be used is the peritoneoscope, which allows for examination inside your abdomen. This instrument is inserted into an opening made in the abdomen, and a biopsy specimen may also be taken.
If the presence of fluid is indicated by either of these procedures, the doctor may drain it by inserting a needle into the affected area. Removal of chest fluid is called thoracentesis; removal of abdominal fluid is call paracentesis.
Other screening methods for diagnosis of asbestos-related disease include various imaging tests. In addition to X-rays, methods include magnetic resonance imaging (MRI) or positron emission tomography (PET). A more recent and promising screening method is the computed tomography (CT) scan.
Computed Tomagraphy / CT Scan:
Computed tomagraphy, or spiral CT scan, is a special radiographic technique that produces a clear cross-sectional image that allows a radiologist to see distinct aspects of the lung or pleura that are not readily apparent from the standard X-ray image. Recent studies (CHEST 2002;122:15-20 and MAYO CLIN PROC 2002;77:329-333) support the use of annual chest computed tomography (CT scans) exams as a valuable screening tool for people with a high risk of developing lung cancer, including mesothelioma cancer. There does appear to be conflicting assessment as to the cost-effectiveness of CT screening. A 2003 study by Johns Hopkins raises this concern about the cost-effectiveness of CT scans and states, "There is a downside to this, including high costs and possible harm to individuals who may unnecessarily get invasive procedures if the scan detects a benign lung nodule." A more recent study in Chest, 2003:124:614-621 comes to a different conclusion: "A baseline low-dose CT scan for lung cancer screening is potentially highly cost-effective and compares favorably to the cost-effectiveness ratios of other screening programs."
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