The lungs are the main organs for breathing and are part of the respiratory system that includes the nose, mouth, windpipe and airways (large airways, bronchi; smaller airways, bronchioles) to each lung. 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.
Less common types of lung cancers
Less common lung cancers can form in the chest area. These are called ‘thoracic cancers’.
Mesothelioma
Mesothelioma is a rare type of cancer that affects the covering of the lung, called the pleura. It’s almost always caused by exposure to asbestos.
Primary lung cancer is split into two groups:
Non-small cell lung cancer (NSCLC) – the most common type
Types of non-small cell lung cancer include:
- Adenocarcinoma – starts in the mucus and affects the smaller airways
- Squamous cell carcinoma – mainly affects the cells that line the tubes into the lungs. It tends to grow in the centre of the lung. It’s usually caused by smoking
- Large cell carcinoma or undifferentiated carcinoma – cancer affecting large round cells
Small cell lung cancer (SCLC) – This is less common (about 1 in 10 lung cancers). It mainly affects smokers and is very rare in people who’ve never smoked.
SCLC tends to start in the middle of the lungs and usually spreads more quickly than NSCLC.
