Background Alcohol consumption is a well-established risk factor for breast cancer. This association is thought to be largely hormonally driven, so alcohol use may be more strongly associated with hormonally sensitive breast cancers. Few studies have evaluated how alcohol-related risk varies by breast cancer subtype. Methods We assessed the relationship between self-reported alcohol consumption and postmenopausal breast cancer risk among 87 724 women in the Women's Health Initiative Observational Study prospective cohort from 1993 through 1998. Multivariable adjusted Cox regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). All statistical tests were two-sided. Results A total of 2944 invasive breast cancer patients were diagnosed during follow-up through September 15, 2005. In multivariable adjusted analyses, alcohol consumption was positively related to risk of invasive breast cancer overall, invasive lobular carcinoma, and hormone receptor-positive tumors (all P(trend) </= .022). However, alcohol consumption was more strongly related to risk of certain types of invasive breast cancer compared with others. Compared with never drinkers, women who consumed seven or more alcoholic beverages per week had an almost twofold increased risk of hormone receptor-positive invasive lobular carcinoma (HR = 1.82; 95% CI = 1.18 to 2.81) but not a statistically significant increased risk of hormone receptor-positive invasive ductal carcinoma (HR = 1.14; 95% CI = 0.87 to 1.50; difference in HRs per drink per day among current drinkers = 1.15; 95% CI = 1.01 to 1.32, P = .042). The absolute rates of hormone receptor-positive lobular cancer among never drinkers and current drinkers were, 5.2 and 8.5 per 10 000 person-years, respectively, whereas for hormne receptor-positive ductal cancer they were 15.2 and 17.9 per 10 000 person-years, respectively. Conclusions Alcohol use may be more strongly associated with risk of hormone-sensitive breast cancers than hormone-insensitive subtypes, suggesting distinct etiologic pathways for these two breast cancer subtypes.

El consumo de alcohol es un factor de riesgo bien establecidos para el cáncer de mama. Esta asociación se cree que es en gran medida impulsada por las hormonas, por lo que el consumo de alcohol puedenser más fuertemente asociado con cánceres de mama sensibles a las hormonas. Pocos estudios han evaluado cómo relacionar como el alcohol varía el riesgo por el subtipo de cáncer de mama. Se estudió la asociación entre el consumo de alcohol y el riesgo de cáncer de mama posmenopáusica entre 87. 724 mujeres de la Women's Health .Un estudio observacional, prospectivo desde 1993 hasta 1998. multivariable de regresión Todas las pruebas estadísticas fueron de dos caras. Un total de 2.944 pacientes de cáncer de mama invasivo fueron diagnosticados durante el seguimiento a través del 15 de septiembre 2005. En análisis ajustados multivariables, el consumo de alcohol se relaciona positivamente con el riesgo de cáncer de mama invasivo en general, el carcinoma lobular invasivo, y los tumores con receptores hormonales positivos (todos P (tendencia) </ = 0,022). Sin embargo, el consumo de alcohol fue más fuertemente asociado con el riesgo de ciertos tipos de cáncer de mama invasivo en comparación con los demás. En comparación con los no bebedores, las mujeres que consumieron siete o más bebidas alcohólicas por semana tenían un riesgo casi doble del aumento de receptores hormonales positivos al carcinoma lobular invasivo pero no un aumento del riesgo significativo estadísticamente hablando de los receptores hormonales positivos del carcinoma ductal infiltrante. Las tasas absolutas positivas del receptor de la hormona del cáncer lobular de entre los no bebedores y bebedores actuales fueron, 5,2 y 8,5 por cada 10 000 personas/año, respectivamente, mientras que los positivos para el receptor del cáncer ductal hormna fueron de15,2 y 17,9 por 10 000 personas/año, respectivamente. El consumo de alcohol pueden ser más fuertemente asociado con el riesgo de padecer cánceres de mama sensibles a las hormonas que a los subtipos que son insensibles a hormonas, lo que sugiere diferentes vías etiológicas de estos dos subtipos de cáncer de mama.

This is a very well-done analysis of a large dataset from the Women’s Health Initiative. It supports previous research indicating that the lobular subtype of breast cancer (which makes up 15-20% of cancers) is more strongly associated with alcohol than the much more common ductal type of cancer. There was no statistically significant association between alcohol intake and ductal carcinomas. The association of alcohol consumption was seen for hormone + tumours but not for hormone – tumours .Most previous studies have suggested the same association between alcohol intake and oestrogen + breast cancer as this study, but the present study is much larger and permits more precise estimates of effect. There were no significant differences according to type of beverage in this study. "