The lungs are the main organs for breathing and are part of the respiratory system.
The respiratory system also includes the nose, mouth, windpipe (trachea) and airways to each lung. These consist of large airways (bronchi) and smaller airways (bronchioles).
The lungs look like two large, spongy cones.
Each lung is made up of sections called lobes – the left lung has two lobes and the right lung has three.
The lungs rest on the diaphragm, which is a wide, thin muscle that helps with breathing.
What is lung cancer?
Lung cancer is a cancerous tumour in the tissue of one or both of the lungs.
- Primary lung cancer starts in the lungs
- Secondary or metastatic lung cancer can start somewhere else in the body and spread to the lungs.
What are the different types or lung cancer?
There are several types of lung cancer, and these are classified according to the type of cells affected.
Cancers are named for the way the cells appear when viewed under a microscope.
Non-small cell lung cancer (NSCLC)
Types of non-small cell lung cancer include:
- Squamous cell carcinoma – mainly affects the cells that line the tubes into the lungs (bronchi)
- Adenocarcinoma – a type of cancer affecting smaller airways)
- Large cell carcinoma – cancer affecting large round cells under the microscope
There are also less common subtypes of non-small cell lung cancer.
Small cell lung cancer (SCLC)
Small-cell lung cancer tends to start in the middle of the lungs, and it usually spreads more quickly than NSCLC.
Types of small-cell lung cancer include:
- Small cell carcinoma
- Mixed small cell/large cell carcinoma
Less common types of lung cancers
Less common lung cancers can form in the chest (or thoracic) area. These are called ‘thoracic cancers’ and include thymomas, mediastinal tumours and chest wall tumours.
Mesothelioma is a rare type of cancer that affects the covering of the lung (the pleura). It is almost always caused by exposure to asbestos and is very different to lung cancer.