がんの科学と治療

Lung Cancer: Early Diagnosis and Screening

Abstract

David R Baldwin and Richard B Hubbard

Lung cancer accounts for an estimated 1.4 million deaths globally that is, 18.4% of all cancer deaths. More than 35,000 people died from lung cancer in 2008 in the UK. In males this was almost a quarter of all cancer deaths and in females just over a fifth. By comparison, 16% of female cancer deaths were from breast cancer and the second commonest cause of cancer death overall (colorectal) accounts for 10% of all cancer deaths. The majority of people with lung cancer (three quarters in the UK) present with stage IIIb or IV disease where cure is impossible and so survival low in comparison with other common cancers.
 
There are two ways in which we are likely to diminish the huge public health burden that mortality from lung cancer constitutes: smoking cessation and earlier diagnosis. Smoking cessation has already produced dramatic falls in the age-adjusted incidence of lung cancer and it appears that lung cancer incidence has passed its peak in males at least. Continued efforts to reduce the prevalence of smoking across all sectors of society are a key public health priority. However there remains a large population at risk of developing lung cancer. In the US in 2007 there were an estimated 94 million people with a history of smoking and about half of these were current smokers. Thus the second way mortality may be substantially altered by early detection initiatives that lead to diagnosis at an earlier stage. There are, in turn, two ways in which people may be diagnosed earlier: by the use of early diagnosis and awareness initiatives and by population screening. The first of these methods is unproven and the second has only recently been shown to be effective.