Breast cancer is the most common malignancy among women and a leading cause of cancer death among the women in USA and Europe. In Croatia breast cancer is the leading cause of morbidity and mortality from malignant diseases too, especially among women aged 40 to 50 years.1-3
Chronic alcohol consumption is associated with an increased risk for cancers of many organs.4-6 In one study, approximately 3% of all cancers in the United States were attributed to heavy drinking,7 whereas in a recent Japanese study about 13% of cancers among females were found to be due to heavy alcohol drinking.8
The risk for the development of cancer varies from low to moderate and high, depending on the type of organ affected as well as the amount of alcohol consumed, especially in individuals with increased susceptibility to the development of cancer. Epidemiologic evidence has linked light to moderate intake of alcohol to the cancer of colorectal region and female breast. As these cancers are common in the developed countries, even small increases of risk can have the important public health implications.9 An understanding of mechanisms by which the chronic alcohol consumption promotes carcinogenesis is important for development of appropriate strategies for prevention and treatment of alcoholassociated cancers.8
Based on the findings from various studies, 25% to 80% of alcohol-associated cancers are attributed to alcohol. About 4% of breast cancers in the developed countries may be ascribed to alcohol consumption and this association of alcohol consumption and increased risk for breast cancer has been a consistent finding in majority of epidemiologic studies during the past two decades.1-6,10-12
The majority of studies suggest that about 15.1 million persons in United States are alcohol dependent and nearly 4.6 million of them are women. Fifty years ago the ratio of alcohol dependence and abuse in men and women were 10:1, but during the last ten years this relation has changed to 3.6:1, respectively.13
Association of alcohol consumption and breast cancer is important because the breast cancer is a major source of morbidity and mortality among women around the world, because the alcohol consumption is common, and because drinking is modifiable.
The link between the alcohol intake and breast cancer is dependent on the total dose of alcohol consumed. There is an approximate 10% increase in breast cancer for each 10g of daily alcohol consumed. Data suggest that the risk increases with the consumption of alcohol in general, regardless of beverage type.14 Although the specific association between the alcohol consumption and increased risk of breast cancer has been consistent in numerous studies to date, the biologic mechanism remained unknown.12-15
An association between the alcohol consumption and breast cancer was first reported by Williams and Horm.16 Five years later, Rosenberg and colleagues17 observed the alcohol-breast cancer link in 1,152 patients with breast cancer and 2,702 nonmalignant control subjects. They found that the daily alcohol consumption is important: dose-response relationship is defined as relative risk (RR) and the daily alcohol consumption of 25g was set to be RR 1.6,14 Among the women drinking alcohol four or more times per week, compared with the nondrinkers, the breast cancer RR was 2.0-2.5 and for women drinking less than four times per week, RRs were 1.5-1.914 respectively.
Since these findings, a lot of studies concerning the correlation of alcohol and breast cancer, been done.16-25 These studies clearly show that the ingestion of all types of alcoholic beverages is associated with an increased cancer risk, suggesting that ethanol itself is the crucial compound which causes that effect. Multiple mechanisms are involved in the alcohol-associated cancer development. The animal experiments on alcohol and cancer note the effect of chemically induced carcinogenesis. …