Breast Cancer and Alcohol

On the list of proven risk factors for breast cancer, alcohol consumption is now invariably included. This was not always the case, however, as studies performed in the past often achieved contradictory or inconclusive results. But this question has been extensively researched over the last 10-15 years, and much more is now known about the link that actually exists between alcohol consumption and an increased risk of breast cancer.

Confirmation
In the United Kingdom, researchers followed approximately 1.2 million middle aged women over the course of seven years to study, among other things, the possible relationship between their drinking habits and cancer. Results of the so-called Million Woman Study were released in 2009, showing that women who drank alcohol had about 13% more cancers overall than expected, and that the majority of these cases were breast cancer. Researchers estimated that as many as 11% of the breast cancers found in this large group of British women could be traced directly to usage of alcohol. One of the major conclusions reached by the medical authorities who organized this study is that there really is no safe level of alcohol consumption, as even women who would be considered low-level or moderate drinkers proved to be at greater risk for developing breast cancer.

The Women's Health Initiative was begun back in 1991 by the National Institutes of Health in order to look more closely at various health issues faced by older women. The cancer histories of over 88,000 women were tracked for a five-year period as a part of this extensive survey, and it was discovered that there was indeed a real and statistically-demonstrable connection between alcohol consumption and breast cancer. The results of this study confirmed that for postmenopausal women in particular, there is really no safe level of alcohol consumption with respect to breast cancer risk, and the more alcohol that is consumed the more the risk is elevated.

What was especially significant about the results of this study, which were published in 2010 in the online Journal of the National Cancer Institute, is that they proved conclusively that while breast cancer risk was indeed increased by alcohol consumption, this pattern was only relevant with respect to certain kinds of breast cancers – namely, hormone-responsive estrogen-receptor-positive cancers, and invasive lobular carcinoma, or ILC. Neither estrogen-receptor negative nor invasive ductal carcinoma risk were raised by the consumption of alcohol, and noninvasive/non-metastatic breast cancers of the ducts and lobules were also not affected by alcohol use. The risk for breast cancer that combines the two high risk categories – invasive ductal lobular breast cancer that tests positive for estrogen receptors – was 63% greater for women who consumed any amount of alcohol, no matter how modest..