Although cigarette smoking is the most important cause of lung cancer, stopping smoking does significantly reduce the chance of getting the disease.

Smoking 20 cigarettes a day you are about 20 times more likely than non-smoker to get lung cancer.

However, if you stop smoking your risk of developing lung cancer will fall quite rapidly. Within 5 years of stopping the risk will have halved. By 15 to 20 years after stopping your chance of developing lung cancer will be about the same as that of someone who has never smoked.

The age at which you stop smoking is also important. Statistics suggest that if you stop smoking before the age of 35, as you have done, then your life expectancy will be about the same as that of a non-smoker.

So congratulations on having stopped smoking, keep it up!