New findings about alcohol and breast cancer risk

Many women drink alcohol whether it is beer, wine, or liquor and this consumption can increase the risk for developing breast caner. In 2002, the Collaborative Group on Hormonal Factors in Breast Cancer published a report clearly showing a link between alcohol consumption and increased risk of developing breast cancer. In this study, scientists reviewed data from over 153,000 women (over 58,000 women with breast cancer and 95,000 women without breast cancer) who participated in 53 different studies conducted worldwide. Of the several questions explored in this analysis, one focus was to evaluate what contribution alcohol consumption made to altering the risk of developing breast cancer. The overall conclusion was that alcohol consumption raises the risk of developing breast cancer by 7% when those that drink alcohol were compared with those who don’t.

Breast cancer isn’t just one disease. There are multiple forms that it can take: ductal carcinoma, lobular carcinoma, hormone sensitive (estrogen and progesterone receptor positive), hormone insensitive. Ductal and lobular carcinoma arise in different locations -- either in the ducts within the breast (hence ductal) or within the milk producing glands (lobular). Hormone sensitivity means that there is expression of the estrogen receptor and the cancer is responsive to hormones (estrogen and progesterone) or it doesn’t express the receptors and therefore doesn’t respond to hormones. Ductal carcinoma is the most common form (70% of all breast cancers), with lobular carcinoma accounting for 30% of the cases. In the 2002 study, the analysis was between alcohol consumption and the risk of developing any form of breast cancer.

This week, an interesting new article looked at alcohol and breast cancer risk in a new light. Investigators from the Fred Hutchinson Cancer Institute in Seattle explored if alcohol consumption alters the type of breast cancer and focused on whether drinking alcohol contributes to the development of a particular form of breast cancer or if it is more general, affecting multiple forms of cancer. Interestingly, this analysis demonstrated that alcohol consumption raised the risk of developing lobular carcinoma but did not alter the risk of developing ductal carcinoma. In fact, the researchers found that alcohol affected hormone sensitive (estrogen receptor positive) lobular cancer formation.

What does this mean? It shows that different subtypes of cancer respond differently. They develop as a result of different causes and are influenced by different factors. Specifically, alcohol affects the development of lobular but not ductal cancer and uses estrogen in that process. How this happens is still unclear, but these findings are quite intriguing. These findings will help to understand how lobular cancers form and how estrogen affects them. It could lead to new methods to detect these cancers and maybe to how to prevent them in the first place.