Case-control study of colorectal carcinoma in situ and cancer in relation to cigarette smoking and alcohol use (Japan)

Abstract

Acase-control study was performed in order to examine the relation ofcigarette smoking and alcohol use to colorectal carcinoma in situ and cancer,separately. Study subjects consisted of 129 colorectal carcinoma in situcases, 66 colorectal cancer cases, and 390 controls recruited from healthcheck-up examinees in Tokyo from January 1991 to March 1993. Smoking statusand alcohol habit were ascertained from a self-administered questionnaire.Both cumulative cigarette smoking and current smoking status were associatedsignificantly with an increased risk of carcinoma in situ. A statisticallynonsignificant increase in the risk of colorectal cancer was noted only amongthose with the heaviest exposure category of these measures of smoking. Thecumulative exposure to cigarette smoking within recent 20 years wasassociated significantly with an increased risk of carcinoma in situ, whereassmoking until 20 years before the diagnosis was associated significantly withan increase of c ancer risk. A significant and positive association wasobserved between cumulative alcohol drinking and colorectal cancer. Thesefindings suggest that cigarette smoking may act as an initiator in colorectalcarcinogenesis and also provide weak evidence that alcohol drinking isrelated to an increased risk of colorectal cancer.