Lung cancer: introduction

Lung cancer is a major public health concern worldwide. In Scotland, after non-melanoma skin cancer and prostate cancer, lung cancer is the third most commonly diagnosed cancer in men. It is the third most commonly diagnosed  women after non-melanoma skin cancer and breast cancer. Currently, around 2500 men and 2160 women are diagnosed with lung cancer in Scotland every year. Survival is generally poor with less than 10% of patients remaining alive at five years after diagnosis. Hence, lung cancer is the most common cause of death from cancer in both men and women.   

Tobacco smoking is the main risk factor for lung cancer, accounting for an estimated 80-90% of cases in developed countries. The cumulative risk of lung cancer can be reduced by around 90% in smokers who manage to quit before middle age (Peto et al, 2000; Crispo et al, 2004). Thus smoking cessation policies and services play a major part in the primary prevention of lung cancer.

Trends in incidence of, and mortality from, lung cancer reflect historic trends in smoking prevalence in Scotland (see the prevalence trends graph in the tobacco section of the website). In common with several other countries, incidence rates of adenocarcinoma (subtype of lung cancer) have increased over time, perhaps associated with changes in cigarette design, although squamous cell carcinoma remains the predominant type of lung cancer among men in Scotland (Harkness et al, 2002).

It has been shown that, per cigarette smoked the risk of developing lung cancer is higher in the west of Scotland than in some other countries high risk cohorts (see graphic in Gilles et al, 1988 paper).

It is expected that the age-standardised incidence rate of lung cancer will continue to decrease in men, and will begin to fall in women up to the period of 2016-2020 (Scottish Executive, 2004 (Cancer Scenarios publication)). Since lung cancer arises more commonly in the elderly, the absolute numbers of new cases will not decrease as steeply because of ageing of the population.

In the past, several randomized trials of screening by chest x-ray and sputum cytology did not demonstrate a reduction in mortality from lung cancer. The advent of low-dose spiral CT scanning has re-awakened interest in screening for lung cancer, and several trials are underway in different countries (USA, The Netherlands and France).