How is lung cancer diagnosed?

The diagnostic tests used for lung cancer can vary from patient to patient, as there are numerous other factors that doctors look into while diagnosing a patient such as medical history, symptoms and findings from previously conducted physical examinations.

The commonly used diagnostic methods for lung cancer are listed below:

Imaging tests

Imaging tests are important when it comes to diagnosing lung cancer as these imaging tests enable doctors to understand the location of the cancer,  to see how far it has spread, to see if treatment is working and to understand if the cancer is coming back. They various imaging tests conducted are listed below:

Computed tomography  (CT)

In this kind of an imaging method, X-ray machines are combined with a computer to give a cross-sectional view of the lungs.  CT is the most common method used as the images produced are of good quality and the abnormalities that can be detected are up to 90%.

Positron emission tomography (PET) scan

In a PET scan, a type of radioactive sugar is injected into the patient’s bloodstream and since cancer cells consume large amounts of sugar quickly, a camera is used to spot this kind of radioactivity. This type of an imaging test is also used to understand if the cancer has spread to other parts of the body.

Other procedures used in the diagnosis of lung cancer

To see if the patient really has lung cancer, doctors collect tissue or fluid from around the lungs and carefully test it to see if cancer cells are present.  The tests conducted are listed below.

Sputum cytology

Sputum cytology is a kind of diagnostic test that is conducted wherein a sample of the mucus that contains blood is taken and view under a microscope to check for the presence of abnormal cells.


The procedure of a bronchoscopy is done by doctors to usually check if there is a tumor or fluid in the lungs. In this procedure a tube known as a bronchoscope is passed through the use or mouth and into the airways.


Mediastinoscopy is a kind of endoscopy wherein a incision is made at the base of the neck and surgical tools are inserted behind the breastbone to take tissue samples from the lymph nodes.

Fine needle biopsy (FNAC)

In the fine needle biopsy test a fine needle is used to scrape off cells from the affected area. These cells are further examined under a microscope to see if they are cancerous.


A biopsy is a medical procedure that consists of the removal of a small amount of tissue that is later studied under a microscope by a pathologist to see if it is cancerous or not. There are also other tests that can suggest if the tissue is cancerous but a biopsy is a more definitive method. It is gold standard test for cancer diagnosis.

Biopsy for Lung tumor is usually done under USG or CT guided or along with bronchoscopy or mediastinoscopy.

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