本文回顧綜述近年來肺癌的流行病學特徵及危險因子之文獻。臺台灣地區的肺癌發生率在三十年來增加近八倍，是增加最快的癌症之一。按其增加的速率估計，在二十一世紀初可能就會成為國人最重要的癌症。在基礎醫學、臨床醫學及流行病學上，都有一致的證據顯示吸菸走肺癌最重要的因子，二手菸暴露也被證實為肺癌之危險因子。職業及居家之氧氣暴露及其他化學致癌物如：石綿、砷、多環芳香煙的暴寒，以及遺傳之易罹癌性、營養攝取不足也走重要的致病因子。吸菸率偏低的華人女性卻有偏高的肺癌發生率，其重要危險因子有待探討，烹調油煙、二手菸、遺傳之易罹癌性、性荷爾蒙都是值得鑽研的主題。初級預防走防治肺癌的根本之道，低焦油香菸不能根本解決問題，戒菸才是最為重要。化學預防可能會降低戒菸者之肺癌發生卒，但目前所得到的結果卻仍有爭議。早期發現癌症也走防治肺癌的新方向，利用痰細胞學檢驗輔以單株抗體進行免疫細胞化學分析法，是一個有潛力的篩檢工具。p53 基因的突變，有可能成為早期診斷的指標。

　　　　　This article reviews the researches on the epidemiologiccharacteristics and risk factors of primary lung cancer in the recent decade.Primary lung cancer incidence and mortality have been increasing rapidly duringpast thirty years in Taiwan. Consistent evidences in basic researches, clinicalobservations, and epidemiological studies have shown that cigarette smoking isthe most important risk factor for lung cancer. Environmental tobacco smokinghas also been documented as lung cancer risk factor. Occupational and domesticradon exposure and other occupational hazards, including asbestos, arsenic, andpolycyclic aryl hydrocarbon have also been reported to be associated with thedevelopment of lung cancer. The association of genetic susceptibility andmicro-nutrients with lung cancer needs further assessment. The low prevalence ofcigarette smoking and relatively high incidence rate of primary lungadenocarcinoma among Chinese and Taiwanese women suggests the existence of someimportant risk factors to be elucid. The associations with lung cancer risk forcooking oil fumes, history of lung diseases, and reproductive factors have beenintensively investigated. Among the strategies toward the prevention of lungcancer, smoking cessation is the most important. Chemoprevention may reduce therisk of lung cancer among ex-smokers, but there remains debates about theprotective effect of b-carotene and retinoids. Early detection is an alter-native to reduce lung cancer mortality. Immuno-cytochemical analysis of sputumusing monoclonal antibody may be a potential tool for the screening of lungcancer. Polymerase chain reaction aiming to search for an activated ras gene orp53 mutation from exfoliated bronchial epithelial cells is another promisingtechnique for early detection of lung cancer.