Objectives: To explore the effectiveness of alcohol drinking and tobacco smoking cessation in reducing esophageal cancer risk, taking into account the key characteristics of each habit and the simultaneous exposure to both habits.
Methods: Data from a series of five hospital-based case-control studies of incident squamous-cell carcinoma of the esophagus conducted by the International Agency for Research on Cancer (IARC, Lyon, France) in high-risk areas in South America were combined and analyzed by multivariate logistic regression procedures. A total of 2063 men (655 case patients and 1408 control subjects) were included in the pooled analysis.
Results: For either habit, the risk of esophageal cancer decreased rapidly, strongly and significantly with longer periods of abstention. The risk reduction was statistically significant regardless of the intensity and duration of each habit and the type of tobacco or alcoholic drink consumed. For subjects exposed to both risk factors, the protective effect of quitting both habits appeared to be synergistic, reaching, after only five to nine years of simultaneous cessation of both exposures, a 70% risk reduction, a reduction that clearly overlapped with the risk intervals of both never-smokers and never-drinkers. The risk benefit of merely quitting alcohol drinking was delayed (>10 years of cessation) unless it was also accompanied by a few years of smoking cessation.
Conclusions: Our findings solidly demonstrate for the first time the effectiveness of smoking and drinking cessation in reducing esophageal cancer risk. For the large proportion of subjects in the general population exposed to both risk factors, our results further emphasize the importance of smoking cessation to effectively reduce cancer risk.