Alcohol linked to less common breast cancer

A new study shows alcohol increases risk of hormone-positive

lobular cancer.
Illustration courtesy of the National Cancer Institute.

SEATTLE – Cancer Digest – Women who drink alcohol more than once a day have twice the risk of a less common form of breast cancer called lobular carcinoma, a new study shows.

Led by Dr. Christopher Li, researchers at Fred Hutchinson Cancer Research Center analyzed a subset of women who took part in the Women’s Health Initiative (WHI) and answered a questionnaire that included questions about alcohol consumption. Their study was published today online in The Journal of the National Cancer Institute.

"We found that women who drank one or more drinks per day had about double the risk of lobular type breast cancer, but no increase in their risk of ductal type breast cancer,” the authors wrote. “It is important to note that ductal cancer is much more common than lobular cancer accounting for about 70 percent of all breast cancers whereas lobular cancer accounts for only about 10 percent to 15 percent of cases."

The report confirms a number of studies showing a link between breast cancer and alcohol, and most of those showed that alcohol was strongly linked to hormone-receptor positive cancer. Few studies, however, have looked at the relationship between alcohol use and breast cancer risk by whether the cancer started in the milk ducts, called ductal breast cancer, or in the milk-producing lobules, called lobular cancer.

The researchers looked at the follow-up data from the 2,944 women in the WHI study who developed invasive breast cancer by tumor subtypes, hormone status, alcohol consumption, demographic and lifestyle factors, as well as family and reproductive history. The researchers categorized the women by those who never drank, those who formerly drank and those who currently drank. Those who drank were further grouped into six categories according to the average number of drinks per week, starting from less than one drink per week to more than 14 drinks per week.

The researchers found that alcohol use was more strongly related to the risk of lobular carcinoma than ductal carcinoma, and more strongly related to hormone-receptor-positive breast cancer than hormone-receptor-negative breast cancer. The risks observed did not vary by the type of alcohol women consumed.

The authors cautioned that the study's primary weakness is that alcohol usage was only evaluated at the beginning of the study, and there was no information on the women’s past alcohol usage, nor their subsequent usage.

SOURCE: adapted from press materials provided by the Journal of the National Cancer Institute and Fred Hutchinson Cancer Research.