Epidemiology of alcohol-associated cancers.

Alcohol, especially in combination with smoking, is a well-established risk factor for cancers of the oral cavity and pharynx, esophagus, and larynx, with 25% to 80% of these cancers being attributable to alcohol. Rates of these cancers in the United States have been decreasing in recent years, possibly because of reductions in cigarette smoking and alcohol use. Chronic alcohol consumption has been linked with increased risk of liver cancer in epidemiologic studies. However, the rising rates of this cancer in the United States are most likely due to the increasing prevalence of chronic hepatitis B and C infections. Epidemiologic evidence has linked light to moderate intake of alcohol to cancers of the colorectum and female breast. These cancers are common in developed countries, so even small increases in risk can have important public health implications. Although results of most epidemiologic studies have provided little or no support for a causal relation between light and moderate alcohol use and risk of pancreatic cancer, a possible role of heavy alcohol consumption cannot be ruled out. Further studies of these cancers are needed to clarify the role of type of alcoholic beverage, the role of alcohol concentration, and the dose-response curve at low concentrations of alcohol. Future research also should be designed to promote the use of uniform ways to report alcohol intake and uniform measures for analysis, to include the investigation of alcohol-associated cancer risks in U.S. minority populations, to enhance experimental work to better understand the underlying mechanisms through which alcohol promotes carcinogenesis, and to develop preventive strategies.