Studies Shed Light on Breast Cancer and Alcohol Link

Two new studies examine why some women who drink alcohol are at higher risk for breast cancer or recurrence of the disease than others.

Previous research established alcohol as a risk factor for breast cancer, but “few studies have evaluated how alcohol-related risk varies by breast cancer subtype,” wrote Christopher I. Li, M.D., Ph.D., of Fred Hutchinson Cancer Research Center and colleagues in the first study.

Medical News Today reported Aug. 23 that the researchers looked at tumor subtypes, alcohol consumption, and health and lifestyle characteristics of 2,944 participants in the Women's Health Initiative (a long-term study of health outcomes in postmenopausal women) who had invasive breast cancer.

Compared with abstainers, women who consumed 7 or more drinks per week had no increased risk for ductal carcinomas (the most common form of breast cancer, occurring in the ducts that carry milk); but they were at increased risk for lobular carcinoma (a less common form, occurring in the milk production area of the breast).

Researchers also found a stronger link between alcohol and hormone-sensitive breast cancer compared with hormone-insensitive breast cancer. The findings suggest “distinct etiologic pathways for these two breast cancer subtypes,” concluded the authors.

According to another study, certain women who drink alcohol may be at increased risk for breast cancer recurrence, HealthDay News reported Aug. 30.

Marilyn L. Kwan, Ph.D., of Kaiser Permanente, and colleagues asked 1,900 women diagnosed with early-stage breast cancer to complete a baseline dietary survey including their alcohol consumption. 

At seven-year follow-up, even moderate drinking (consuming three or four drinks per week of any type of alcoholic beverage) raised the risk for breast-cancer recurrence by 1.5 times, but only in women who were postmenopausal, overweight, or obese.

Women who consumed less than three to four drinks per week had no increased risk of recurrence. However, consuming any amount of alcohol may have reduced the risk of dying from causes other than breast cancer.

The findings will need to be confirmed by further research, said Kwan.

The studies were published online in the Journal of the National Cancer Institute and the Journal of Clinical Oncology.