Lung Cancer : Diagnosis

Doctors use a wide range of diagnostic procedures and tests to diagnose lung cancer.

(A) Chest X-ray : The procedure involves a view from the back to the front of the chest as well as a view from the side. Chest X-rays may reveal suspicious areas in the lungs but are unable to determine if these areas are cancerous.

(B) CT (computerized tomography, computerized axial tomography, or CAT) scans may be performed on the chest, abdomen, and/or brain to examine for both metastatic and lung tumors.

A CT scan of the chest may be ordered when X-rays do not show an abnormality or do not yield sufficient information about the extent or location of a tumor.

(C)Low-dose helical CT scan (or spiral CT scan) is sometimes used in screening for lung cancers. This procedure requires a special type of CT scanner and has been shown to be an effective tool for the identification of small lung cancers in smokers and former smokers.

(D) Magnetic resonance imaging (MRI) scans may be appropriate when precise detail about a tumor’s location is required. The MRI technique uses magnetism, radio waves, and a computer to produce images of body structures.

(E) Positron emission tomography (PET) scanning is a specialized imaging technique that uses short-lived radioactive drugs to produce three-dimensional colored images of those substances in the tissues within the body. While CT scans and MRI scans look at anatomical structures, PET scans measure metabolic activity and the function of tissues. PET scans can determine whether a tumor tissue is actively growing and can aid in determining the type of cells within a particular tumor.

(F) Bone scans are used to determine whether a lung cancer has metastasized to the bones.

(G) Sputum cytology: The diagnosis of lung cancer always requires confirmation of malignant cells by a pathologist. If a tumor is centrally located and has invaded the airways, this procedure, known as a sputum cytology examination, may allow visualization of tumor cells for diagnosis.

(H) Bronchoscopy: Examination of the airways by bronchoscopy (visualizing the airways through a thin, fiberoptic probe inserted through the nose or mouth) may reveal areas of tumor that can be sampled (biopsied) for diagnosis by a pathologist.

(I) Needle biopsy: Fine needle aspiration (FNA) through the skin, most commonly performed with radiological imaging for guidance, may be useful in retrieving cells for diagnosis from tumor nodules in the lungs. Needle biopsies are particularly useful when the lung tumor is peripherally located in the lung and not accessible to sampling by bronchoscopy.

(J) Thoracentesis: Sometimes lung cancers involve the lining tissue of the lungs (pleura) and lead to an accumulation of fluid in the space between the lungs and chest wall (called a pleural effusion). Aspiration of a sample of this fluid with a thin needle (thoracentesis) may reveal the cancer cells and establish the diagnosis.

(K) Major surgical procedures: If none of the aforementioned methods yields a diagnosis, surgical methods must be employed to obtain tumor tissue for diagnosis. These can include mediastinoscopy (examining the chest cavity between the lungs through a surgically inserted probe with biopsy of tumor masses or lymph nodes that may contain metastases) or thoracotomy (surgical opening of the chest wall for removal or biopsy of a tumor).

(L) Blood tests: While routine blood tests alone cannot diagnose lung cancer, they may reveal biochemical or metabolic abnormalities in the body that accompany cancer.

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