The World Health Organisation estimates that over 900,000 new cases of lung cancer were diagnosed worldwide in 2000. However, the incidence of lung cancer is not the same in all countries with some of the highest rates in New Zealand and the US and the lowest rates in India, Africa and South America.

Lung cancer is most commonly diagnosed in people in the age range of 55-65 years old. Although the incidence of lung cancer is now falling in men, it continues to rise in women.

There are two main types of lung cancer:

• Small Cell Lung Cancer (SCLC)– which accounts for 20% of all lung cancers and which tends to be more aggressive and often diagnosed at an advanced stage
  
  
• Non-Small Cell Lung Cancer (NSCLC) – which accounts for 80% of all lung cancers. It can be sub-divided into 3 types:
  - adenocarcinoma
  - squamous cell 
  - large cell lung cancer