肺癌検診における喀痰細胞診

摘要

目的．大阪肺癌集検研究班が担当してきた肺癌集検での喀痰細胞診の成績を検討した．対象と方法．大阪府下8市町の一般住民を対像として，1981年より胸部X線間接撮影と喀痰細胞診による肺癌検診を行ってきた．喀痰細胞診は40歳以上で喫煙指数400以上の者，および血痰の自覚症状を有する者（高危険群）を対象とした．成績．1981年から2000年の20年間の受診者総数は297，628人で，この中から235人の肺癌を発見した．喀痰細胞診を行った高危険群からは，130人の肺癌が発見され扁平上皮癌は64人であった．そのうち36人が肺門部扁平上皮癌で喀疾による発見は34人であった．喀痰細胞診で発見された扁平上皮癌は10万対110と20年間で変わらないが，肺門部扁平上皮癌が1996年以降では約1/2に低下した．結論．喀痰細胞診は，肺門部早期扁平上皮癌の発見に不可欠な検査で，肺癌発見率を上昇させるためには高危険群特に50歳以上の男性の多い集団を対象とした検診を行うべきである．さらに十分な精度管理のもとに喀痰細胞診の精度を高めることが必要である．Objective. The effectiveness of sputum cytology screening for detection of lung cancer in Osaka Lung Project was studied. Methods. Participants who were 40 years of age or older and with a cigarette index of 400 or more were screened annually by both sputum cytology and chest X-ray for the early detection of lung cancer in 8 local communities in Osaka since 1981. Results. In the Osaka Lung Project, during the 20 year period from 1981-2000,235cases of lung cancer were detected among 297,628 participants. Lung cancers were detected in 130 high-risk persons. Of the 130 cases, 64 cases were squamous cell carcinoma. Thirty-six of these 64 persons were central-type squamous cell carcinoma. Out of the 36 cases 34 were detected by sputum cytology. The detection rate of central-type squamous cell carcinoma by sputum cytology for recent 5 years since 1996 decreased to about a half of the previous 15 years. Conclusion. Sputum cytology is the most effective method for detection of central type early lung cancer in high-risk group. To improve the detection rate of lung cancer by sputum cytology, it is important to screen the high risk group of over 50 years old men and to control the quality of sputum cytology.