Slattery Martha L, Edwards Sandra, Curtin Karen, Schaffer Donna, Neuhausen Susan
Health Research Center, University of Utah, Salt Lake City, Utah 84108, USA.
Cancer Epidemiol Biomarkers Prev. 2003 Sep;12(9):882-9.
Cigarette smoking has been identified as a risk factor for colon cancer, however, much less is known about the association between cigarette smoking and rectal cancer. The purpose of this article is to evaluate the associations between rectal cancer and active and passive cigarette smoking and other forms of tobacco use. We also evaluate how genetic variants of GSTM-1 and NAT2 alter these associations. A population-based case-control study of 952 incident rectal cancer cases and 1205 controls was conducted. Detailed tobacco use information was collected as part of an interviewer-administered questionnaire. DNA was extracted from blood to examine genetic variants of GSTM-1 and NAT2. Cigarette smoking was associated with an increased risk of rectal cancer in men [odds ratio (OR)=1.5, 95% confidence interval (CI), 1.1-2.1 for current smokers; OR=1.7, 95% CI, 1.3-2.3 for smoking >20 pack-years of cigarettes relative to never-smokers]. After adjusting for active smoking, exposure to cigarette smoke of others also was associated with increased risk among men (OR=1.5, 95% CI, 1.1-2.0). Neither GSTM-1 genotype nor NAT2-imputed phenotype was independently associated with rectal cancer. However, the risk associated with smoking cigarettes among those who were GSTM-1 null relative to those who never smoked and had the GSTM-1 present genotype was OR=2.0 (95% CI, 1.2-3.3). This interaction was of borderline significance (P=0.08). Men who had the combined GSTM-1 present genotype and who were rapid acetylators had no increased risk from cigarette smoking. There were no significant associations between cigarette smoking and rectal cancer among women. This study shows that men who smoke cigarettes, especially those who smoke >20 pack-years, are at increased risk of rectal cancer. This association may be influenced by GSTM-1 genotype. Furthermore, exposure to cigarette smoke of others may increase risk of rectal cancer among men who do not smoke.
吸烟已被确认为结肠癌的一个风险因素，然而，关于吸烟与直肠癌之间的关联却知之甚少。本文旨在评估直肠癌与主动和被动吸烟以及其他形式烟草使用之间的关联。我们还评估了谷胱甘肽S-转移酶M1（GSTM-1）和N-乙酰基转移酶2（NAT2）的基因变异如何改变这些关联。开展了一项基于人群的病例对照研究，纳入952例新诊断的直肠癌病例和1205名对照。作为访员管理问卷的一部分，收集了详细的烟草使用信息。从血液中提取DNA以检测GSTM-1和NAT2的基因变异。吸烟与男性直肠癌风险增加相关[优势比（OR）=1.5，95%置信区间（CI）为1.1 - 2.1（当前吸烟者）；相对于从不吸烟者，吸烟超过20包年的OR = 1.7，95% CI为1.3 - 2.3]。在调整主动吸烟因素后，接触他人的香烟烟雾也与男性风险增加相关（OR = 1.5，95% CI为1.1 - 2.0）。GSTM-1基因型和NAT2推断表型均与直肠癌无独立关联。然而，相对于从不吸烟且具有GSTM-1野生型基因型的人，GSTM-1基因缺失者吸烟相关风险为OR = 2.0（95% CI为1.2 - 3.3）。这种相互作用具有临界显著性（P = 0.08）。具有GSTM-1野生型基因型且为快速乙酰化者的男性吸烟无风险增加。吸烟与女性直肠癌之间无显著关联。这项研究表明，吸烟的男性，尤其是吸烟超过20包年的男性，患直肠癌的风险增加。这种关联可能受GSTM-1基因型影响。此外，接触他人的香烟烟雾可能增加不吸烟男性患直肠癌的风险。
