Lung cancer is usually suspected when a chest X-ray shows a shadow on the lung.
To confirm the diagnosis, a doctor will examine phlegm or mucus that is coughed up. A lesion (an area of damaged or abnormal tissue) found on a chest X-ray can be confirmed by a CT scan of the chest, and a long needle can be placed through the chest under CT guidance to biopsy (take a sample of) the lesion.
Doctors will usually examine the lungs through a viewing instrument inserted into the bronchi. This procedure is called a bronchoscopy. A biopsy may also be done during the bronchoscopy.
During a biopsy, a sample of tissue is removed from the tumour and later inspected with a microscope. Tissue for a biopsy may also be surgically removed by opening the chest.
If you have any questions about lung cancer diagnosis, speak to your doctor.