Abstract 139: Alcohol and breast cancer subtypes in a Spanish cohort.

Background Although alcohol intake is an established risk factor for overall breast cancer, few studies have looked at the relationship between alcohol use and breast cancer risk by subtype of breast cancer. Materials and Methods A population-based study was conducted in Galicia, Spain. A total of 1211 Spanish women diagnosed with operable invasive breast cancer between 1997 and 2010 and 550 controls participated in the study. Data on demographics, breast cancer risk factors, and clinico-pathological characteristics were collected. The four major breast cancer subtypes [hormone-receptor-positive, HER2-negative (luminal A); hormone-receptor-positive, HER2-positive (luminal B); hormone-receptor-negative, HER2-negative (triple-negative); and hormone-receptor-negative, HER2-positive (HER2 over-expressing)] were compared on their clinico-pathological characteristics and risk factor profiles, particularly alcohol intake and reproductive variables. Results With the exception of Her2 overexpressing, the risk of all subtypes of breast cancer increased with increasing alcohol intake (luminal A: OR=2.32, 95%CI:1.43-3.77; luminal B: OR=2.03, 95%CI 1.01-4.06, and triple negative: OR=2.36, 95%CI 1.11-5.00). The association of alcohol with breast cancer was similar among women who drank wine exclusively and other drinkers. The alcohol-breast cancer association appeared to be more pronounced among lobular breast cancers (OR= 2.70, 95% CI:1.33-5.52) than among ductal type breast cancers (OR= 2.09, 95%CI:1.33-3-01). It has been suggested that the association of alcohol intake with breast cancer may be stronger in women who are current or past users of hormone replacement therapy compared with never users, or among non-ovariectomized compared to ovariectomized women, we found no such differences. Conclusions To our knowledge, no prior study has examined the association of breast cancer with alcohol intake according to breast cancer subtypes and the type of wine consumed in Spanish women. Our findings indicate that breast cancer risk increased with increasing alcohol intakes for three out of the four major subtypes of breast cancer and that the risk was similar in women who drank wine, beer and/or liquor exclusively or in mixture. Citation Format: Manuela Gago-Dominguez, Carmen M. Redondo, Manuel Enguix, Maite Pena Fernandez, Maria Elena Martinez, Victor Munoz, Angel Carracedo, Francisco Gude, Jose Esteban Castelao. Alcohol and breast cancer subtypes in a Spanish cohort. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 139. doi:10.1158/1538-7445.AM2013-139