Efficacy of Lung Cancer Screening

Abstract

Lung cancer screening with chest x-ray is not recommended as a public health policy in most countries, since randomized controlled trials have not demonstrated a reduction in lung cancer mortality. In Japan, lung cancer screening with chest x-ray and/or sputum cytology has been introduced since 1987 under the Health and Medical Services Law for the Aged. The efficacy of the screening was evaluated mainly by case-control studies, and some beneficial effects have been suggested. It has been criticized, however, that case-control studies are vulnerable to several biases. Also, time trends for age-adjusted incidence and mortality rates of lung cancer appear almost parallel for these decades, which means no beneficial effects due to early detection at the nationwide level. Therefore, it is not justifiable to state that efficacy of lung cancer screening with chest x-ray has been proved, unless the differential trends of incidence and mortality of lung cancer are clearly observed.