The changing epidemiology of lung cancer.

The 20th century witnessed the scourge of lung cancer as the disease rapidly rose the ranks to become the commonest cause of cancer mortality in the world. Epidemiological evidence conclusively associated cigarette smoking with the causation of lung cancer in the 1950s. Since then and the few decades after, lung cancer of the squamous cell or small cell histological subtypes was mainly diagnosed among male smokers in developed countries. As we move into the 21st century, the incidence of lung cancer is unlikely to abate but the burden will shift from the developed to the less-developed countries. Other epi-demiological changes of lung cancer include the narrowing of the gap between men and women affected by the disease, predominance of the adenocarcinoma histological subtypes as well as more never-smokers afflicted with the disease. Unless we eliminate tobacco smoking completely, lung cancer will continue its wrath into the 21st century.