Non-Small Cell Lung Cancer - Diagnostic Tests

Highlights	Diagnostic Tests	Chemotherapy Treatments
Introduction	Complications	Investigative Agents
Causes	Staging Systems	Resources
Symptoms	Treatment Options by Stages	References
Risk Factors	Surgical Procedures
Lifestyle Changes	Radiation Treatments

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Diagnostic Tests

Chest X-Rays. In a small percentage of cases, a routine chest x-ray reveals the first signs of lung cancer. Usually, however, symptoms of existing lung cancer, such as coughing, chest pain, and blood in the sputum, will lead to a chest x-ray. If non-small cell lung cancer is present, chest x-rays may show lesions in the center of the lung, cavities formed by squamous cell carcinoma, or thread-like infiltrates running through the lungs. By the time lung cancer is diagnosed by chest x-rays, however, it usually has already spread so far that it cannot be surgically cured. Four major studies found no survival benefits in early detection from chest x-rays and sputum screening. Regular screening for lung cancer using x-rays is therefore not currently recommended.

Computed Tomography. Computed tomography (CT), particularly the specific technique called low-dose spiral (or helical) CT, is more effective than x-rays for detecting cancer in patients with suspected lung cancer. It is the standard imaging procedure for determining if and where the cancer has spread (metastasized), for example to the head, bone, or abdomen. It is also used for evaluating patients before lung surgery.

CT stands for computerized tomography. In this procedure, a thin X-ray beam is rotated around the area of the body to be visualized. Using very complicated mathematical processes called algorithms, the computer is able to generate a 3-D image of a section through the body. CT scans are very detailed and provide excellent information for the physician.

The use of helical CT for early screening is being debated. Studies of smokers who were given CT scans suggest that early screening will detect about 2% of lung cancers and most of these in early stages. In the studies, 62% to 82% of the patients with stage 1A cancer were still alive at five years. It should be noted, however, that neither study was controlled and the figures were likely to be higher than in actual practice.

Click the icon to see an image of a CT scan of the chest.

The evidence on survival benefits of early detection is not clear, however, and many experts are highly opposed to widespread screening for lung cancer. For example, some evidence suggests that non-small cell lung cancer cells are often highly aggressive at microscopic levels. If this is true, then the cancer would be highly likely to have already spread long before it was visible with CT scans. In fact, some studies have found no association between tumor size at the time of diagnosis and survival times. Conversely, some malignancies caught on CT scans may actually be very slow-growing nodules and so such patients might be more likely to die from aggressive treatments than from the cancer itself.