More advanced colonic cancer among smokers

Clinical records of 392 patients with adenocarcinomas of the colon were reviewed. Tumors identified in smokers had been diagnosed more often at an advanced stage. In comparison with tumors identified in nonsmokers, those of smokers were much less likely to be Modified Dukes' Stage A (3.9% versus 12.2%) (P less than 0.001), less likely to be Stage B (30.1% versus 39.0%) or Stage C (23.3% versus 26.8%), and nearly twice as likely to be Stage D (42.7% versus 22.0%) (P less than 0.001). The duration of symptoms before diagnosis was similar for smokers and nonsmokers. Age-corrected, 2-year and 5-year survivals were similar for smokers and nonsmokers after correction for the more advanced disease of smokers at diagnosis. The association between smoking and tumor stage was independent of age, sex, tumor location, and date of diagnosis. These observations suggest that environmental stresses may be able to modify tumor-host interrelationships. Smoking-associated changes seem most likely to reflect alterations in host immune anti-tumor defenses.