Published in Stanford Women's Health Magazine

Breast cancer is the most common female cancer in the United States. Breast cancer is the 2nd most common cause of cancer-related death i.e., after lung cancer. It is the leading cause of death in women between 45-55 years of age.  Strongest risk factors include age, gender, family history and genetic factors. Age at menarche, first live birth, and menopause, history of benign breast disease, lifestyle and dietary factors, reproductive and hormonal factors, exposure to ionizing radiation, and environmental factors
may also impact a woman’s risk of breast cancer.  In the fall of 2007, the media reported on a
presentation of findings of a study conducted by Kaiser-Oakland, California physicians that found an increase incidence of breast cancer in women who drank moderate amounts of alcohol. Although findings of this particular study have not been published yet, several studies have linked alcohol consumption to an increase risk of postmenopausal breast cancer. Two hypotheses of why this could be are: (1) through the estrogen pathway and (2) alcohol acting as a co-carcinogen.

Alcohol may be predominantly associated with breast cancers expressing hormone receptors. Approximately 60% of all breast cancers are hormone dependent. There are only 3 prospective studies that have examined the association of alcohol on breast cancer subdivided by receptor status: the Iowa Women’s Health Study, the Swedish Mammography Cohort study, and the Women’s Health study. In the Iowa Women’s Health Study, alcohol intake was most strongly associated with estrogen receptor (ER)- progesterone receptor (PR) - tumors. In contrast, in both the Swedish Mammography Cohort and Women’s
Health studies, alcohol intake was associated with ER+PR+ and not with ER-PR- tumors. A pooled estimate of the data from these 3 studies reported in the Women’s Health Study found a positive association for ER+PR+ tumors and not for ER-PR- and ER+PR- tumors. Hypotheses about how alcohol may act through hormone-dependent mechanisms and/or as a co-carcinogen exist but are unproven.
Interestingly, in the Women’s Health Study, red wine was not associated with an increase risk of breast cancer but beer, liquor, and white wine were.


These studies are examples of study designs that have known limitations that may include recall bias, selection bias, and confounding.  The question of whether breast cancer recurrence in women with advance disease is affected by alcohol consumption is not well studied. Epidemiologic data shows a weak association (i.e., relative risk of approximately 1.2) between alcohol consumption and the diagnosis of breast cancer. The literature indicates that women diagnosed with early stage breast cancer are more likely to die from other causes (i.e., heart disease which seems to be attenuated by moderate alcohol consumption), while women with advanced disease are likely to succumb to complications of breast cancer. The data with regard to moderate alcohol consumption and effects on all cause morbidity and mortality would therefore appear to be applicable to the subset of breast cancer patients diagnosed early. The decision to drink moderately is clearly individualized based on all medical and health issues, as well as perceived quality of life.

 

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