Non-Small Cell Lung Cancer - Diagnostic Tests

Mediastinoscopy. Mediastinoscopy uses a tube inserted between the lungs to locate the appropriate areas for biopsy. It is performed if the physician suspects that cancer has spread to nearby lymph nodes but has not yet metastasized.

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Laboratory Tests

Sputum Analysis for Presence of Cancer Cells. Some experts are now recommending an analysis of coughed-up sputum as a useful and cost-effective measure for identifying cancer cells, particularly those located in central areas of the lung. However, although sputum analysis appears to be as accurate as any other screening test currently conducted, it may miss cancers such as adenocarcinoma, which form in mucus-producing cells typically in the outer portion of the lungs. If a sputum analysis does not show cancer cells, but other signs of lung cancer are present, including blood in the sputum and suspicious areas on X-rays, then other tests are performed.

Biomarkers. Biologic markers, called biomarkers, are high levels of substances that are released by tumors and indicate the presence of specific cancers. Biomarkers can be found in sputum, blood, and tissue samples. They can include enzymes, hormones, amino-acid compounds, antigens (identified by antibodies that specifically target them), growth factors, and other chemicals. Some biomarkers may prove to reveal the presence of cancer cells before they are evident on CT scans or other imaging tests. For example, genetic mutations, notably K-ras and p53, can now be detected in cells found in the sputum or from cells taken during bronchoscopy is now possible. Such mutations occur only with cancerous changes and may enable early detection. Other markers that prove to be important for predicting aggressive cancers are high levels matrix metalloproteinase (MMP)-9 and vascular endothelial growth factor (VEGF), which are compounds involved with angiogenesis (the process in which blood vessels serving the tumor develop).

Other Tests

As part of the doctor's initial examination, patients may undergo pulmonary function testing to evaluate lung strength and capacity. Also, since the cardiac and respiratory systems are often involved in complications following lung cancer surgery, the doctor may be particularly interested in taking a complete history of those systems in prospective surgical patients.