Firstmed Blog

Lung cancer is the second most common cancer in the UK after breast cancer, with more than 37,000 new cases reported a year. The incidence of lung cancer is rising. Lung cancer is responsible for more cancer deaths than colorectal cancer, breast cancer, and prostate cancer combined and makes up 25% of all UK cancer deaths. Lung cancer primarily strikes people age 45 and over and unfortunately by the time an individual develops symptoms, spread has usually occurred. As a consequence the 1 year survival rate is less than 5% and surgical resection is the only cure.

Lung cancer is directly related to smoking with 85% of cases in smokers, 5% in passive smokers and only 10% in non-smokers. In 1950 the British Medical Journal published evidence suggesting a link between smoking and lung cancer, followed by the announcement in 1964 by US Surgeon General Luther Terry that smoking causes lung cancer. More than 50 potential carcinogens have been identified in cigarette smoke which can lead to mutations in genes that predispose to the development of cancer.

A number of different factors are related to the development of lung cancer. Firstly, the more cigarettes smoked, the greater the chance is that you will develop lung cancer however it is the length of time that you have been smoking which is the key determinant.

For example if you were to smoke 20 cigarettes a day for 40 years you are at a greater risk of developing lung cancer than if you smoke 40 cigarettes a day for 20 years. However, when you stop smoking, immediately your risk of lung cancer begins to decrease although it takes on average a further 15 years until your risk of developing lung cancer is equal to that of a non-smoker of the same age. 40% of newly diagnosed lung cancers still occurs in ex-smokers illustrating trhe long interval between quitting smoking and a significant reduction in lung cancer risk.

There has been a change in consumption of cigarettes from unfiltered high tar cigarettes to filtered low tar cigarettes which possibly lead to a slight reduction in lung cancer risk however, this is cancelled out in most smokers who aware of this knowledge take more, deeper puffs or smoke more cigarettes. This change also mirrors the change in incidence seen in different types of lung cancer, from squamous cell carcinomas that metastasise very early on to adenocarcinomas.

The risk in passive smokers (those who don’t smoke but are continuously exposed to second-hand smoke) is very difficult to calculate although it has been estimated that a partner of a smoker has a 25% increased chance of developing lung cancer when compared to a non-smoker.

Furthermore, while cigarette smoking is the main risk factor for developing lung cancer, both cigars and pipe smoking carry an increased risk alongside an increased risk of cancer of the mouth or lips.

Finally, lung cancer always used to be a disease more commonly seen in men due to the smoking patterns of the past however, with an increasing prevalence of women smokers, it is now almost as common in women as in men.