TOBACCO, ALCOHOL, AND COLORECTAL TUMORS - A MULTISTEP PROCESS

A case-control study in the Cote d'Or area of France used the multiste p concept of colorectal carcinogenesis to compare lifetime tobacco con sumption and present alcohol consumption in patients with small adenom as (less than 1 cm, n = 154) or large adenomas (n = 208) and in polyp- free controls (n = 427), Cancer patients (n = 171)were compared with p opulation controls (n = 309). In men, smoking was associated with the risk of adenomas (odds ratio = 3.6 over 20 pack-years vs. nonsmokers, p < 0.001), Alcohol was a risk factor for large adenomas only, with re lative risks of 4.2 (p < 0.01), 3.0 (p < 0.05), and 4.4 (p < 0.01) for consumptions of 20-39, 40-59, and 60 g/day compared with less than 10 g/day. When patients with large adenomas were compared with polyp-fre e controls, both alcohol and tobacco were independently related to the risk of tumor. There was no association between tobacco or alcohol in takes and cancer risk. In women, consumption was much lower in all gro ups, and no significant association with either risk factor was observ ed, These data suggest for the first time that there is an independent effect of alcohol and tobacco in men at different early steps of the adenoma-carcinoma sequence. They demonstrate the usefulness of such a model for etiologic studies on cancer.