Introduction

Primary carcinoma of the lung remains globally the most frequent cause of death from malignancy. Although the incidence of this most fatal of diseases is falling in the USA and some western European countries, it is rising in other parts of the world. The enormous increase in tobacco consumption in Asia portends a rise in this disease in those affected countries. Primary lung cancer will be a global problem for many years to come.

As well as a geographic shift in incidence, the most striking demographic change, at least in “Western” populations, has been the decline in lung cancer in males, yet a rise in women. This is almost certainly due to gender differences in smoking habits in previous decades. In addition there has been a shift in the reported incidence of different cell types. In Western populations squamous cell carcinoma and possibly small cell carcinoma (SCLC) have declined, while adenocarcinoma has risen in frequency. While some classification bias may account for a proportion of this change, these shifts have been attributed to changes in smoking habits, changes in cigarettes themselves and, given their apparent greater propensity to develop adenocarcinoma, the increase in the number of women who smoke.