Lung cancer refers to the uncontrolled growth of abnormal cells in the tissue of one or both lungs, which takes the form of a malignant tumour.11 The cancer can be found in the airway tubes (bronchus) or in the spongy lung tissue (alveoli). Lung tumours may also be caused by cancer which has spread from another part of the body but these are not considered as lung cancer per se.
There are two main sub-classifications of primary lung cancer:
- Non-small cell lung cancer (NSCLC) – this is the most common form of lung cancer, making up approximately 85% of all lung cancer cases. NSCLC can be classified into a number of types, including:1
- Adenocarcinoma – typically found on the outer area of the lungs, in cells that produce mucus
- Squamous cell carcinoma – typically found in the airways of the lungs
- Large cell undifferentiated carcinoma – this type of cancer can not be classified as either adenocarcinoma or squamous cell carcinoma.
- Small cell lung cancer (SCLC) – this type of lung cancer tends to spread faster than NSCLC, however it is less common than NSCLC, accounting for approximately 15% of all lung cancers.1