Alcohol and breast cancer - Review of epidemiologic and experimental evidence and potential mechanisms

The association of alcohol consumption with increased risk for breast cance r has been a consistent finding in a majority of epidemiologic studies duri ng the past 2 decades. Herein, we summarize information on this association from human and animal investigations, with particular reference to epidemi ologic data published since 1995. Increased estrogen and androgen levels in women consuming alcohol appear to be important mechanisms underlying the a ssociation. Other plausible mechanisms include enhanced mammary gland susce ptibility to carcinogenesis, increased mammary carcinogen DNA damage, and g reater metastatic potential of breast cancer cells, processes for which the magnitude likely depends on the amount of alcohol consumed. Susceptibility to the breast cancer-enhancing effect of alcohol may also be affected by o ther dietary factors (such as low folate intake), lifestyle habits (such as use of hormone replacement therapy), or biological characteristics (such a s tumor hormone receptor status). Additional progress in understanding alco hol's enhancing effect on breast cancer will depend on a better understandi ng of the interactions between alcohol and other risk factors and on additi onal insights into the multiple biological mechanisms involved.