Lung cancer in about 25% of the patients may be discovered by chance. A routine chest X-ray or CT scan can detect cancerous growth as a small round mass or when a person is investigated for symptoms suggestive of lung disease.
Medical history and physical examination: If you have signs or symptoms suggestive of a lung disease, your doctor will take a complete medical history, history of smoking and medical history of your family. During examination the doctor will pay close attention to your chest and lungs. If the symptoms on physical examination indicate possibility of lung cancer, further tests will be done. Some tests which might be done include imaging tests (such as chest X-ray, CT scan or MRI scan of the chest), lab tests, and other procedures.
Chest x-ray: This is the most commonly recommended test when any lung disease is suspected. It can show whether there is an infection or tumour in the lung or not. However if the lesion is small or is in place where it is covered by other organs in the chest, it may not be seen on the chest x-ray.
CT scan (computed tomography scan): This is a painless and non-invasive test which provides good visual detail of the part of body that is examined. It can show smaller tumours and other lesions in the lungs which may not be seen on chest X-ray. In CT scan, a series of detailed pictures of any part of the body being examined is taken. A computer then combines these pictures into images of the part of the body that is being studied. The doctor examines the images for abnormalities to see if there is a cancerous growth, infection or any other pathology. CT scan is useful to stage the tumour (that is determine the extent of spread and size of tumour).
MRI: This is also a painless and non-invasive test like CT scan but provides greater visual detail of the part that is being examined as compared to CT scan. It takes a series of detailed pictures of part of the body that is being examined like CT scan and can show small cancerous growth or abnormalities which may not be seen on CT scan.
Biopsy: This is a confirmatory test to diagnose if the lesion is cancerous. For this examination, tissues from the mass or growth suspected to be cancerous is taken and examined for cancer cells. The tissue sample is examined by a pathologist (a doctor who specialises in diagnosing diseases by looking at cells and tissues under a microscope) for cancerous changes.
Sputum cytology: This is a painless and simple test which can be positive in people with lung cancer that is centrally located and has invaded the airways. The sputum is examined for presence of cancer cells under microscope.
Bronchoscopy: This test helps to look at the insides of the airways with help of a special instrument called bronchoscope. It permits your doctor to examine the inside of your airways and take biopsy (a small tissue sample), if the cancer is located in the central areas of the lung or is in larger airways that are accessible to sampling. The tissue is checked for presence of cancer cells, infection etc.
These are some tests that may be done in a person with symptoms suggestive of lung cancer. Other tests which may be done include fine needle aspiration (FNA), thoracentesis, bone scans, and positron emission tomography (PET) scan. If the tests indicate lung cancer, further testing is needed to determine the stage of cancer. Staging helps to decide treatment and predict the prognosis.
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