Epidemiologic studies have long suggested that use of alcohol may increase a womans risk for developing breast cancer, and laboratory studies have shown that alcohol increases the amount of estrogen metabolites available in a womans body, which can then act as a fuel for hormone-sensitive breast cancer. But few studies have looked at alcohols effect on tumor type.
In this study, the researchers reviewed data from the NIH-AARP Diet and Health Study, which began in 1995. Lew and her colleagues analyzed 184,418 postmenopausal women who enrolled in this cohort study, and who answered questions about their daily alcohol consumption. During an average of seven years of follow-up, they found that 70 percent of women in the study drank alcohol; the average amount was a little less than a drink a day. Overall, the authors found that moderate drinking in women increased risk of developing breast cancer.
They then identified 5,461 cases of invasive breast cancer, for which they had tumor type information on 2,391 cases. In all, they analyzed data on 1,641 ER+/PR+, 366 ER-/PR-, 336 ER+/PR-, and 48 ER-/PR+ cases of invasive breast cancer.
The researchers found that ER+/PR+ cancers showed a stronger association with alcohol than that seen in the overall group. Compared to non-drinkers, women who consumed less than one drink daily, one to two drinks, and three or more daily drinks, the increase in relative risk for developing ER+/PR+ breast cancer was 7 percent, 32 percent, and 51 percent, respectively. Although the data suggested increased risks among the women with ER+/PR- breast cancer, the number of cases was relatively small, and this finding was not statistically significant.
The increased risk of invasive breast cancer was observed across different types of alcohol consumed.
Our study at this point provides evidence for the notion that alcohol affects estrogen
|Contact: Staci Vernick Goldberg|
American Association for Cancer Research