Drinking alcohol not likely to increase risk of a breast cancer recurrence

A Kaiser Permanente study provides new information that may help oncologists answer one of the most common questions they hear from breast cancer survivors: Is it safe to drink alcohol?

The new study, published August 9 in Cancer, is the largest prospective study to look at short-term alcohol use after breast cancer. The findings suggest drinking alcohol is not associated with an increased risk of breast cancer recurrence or dying from the disease.

"We know that women who drink alcohol are at increased risk of developing breast cancer and that the risk increases as alcohol use increases," said lead author Marilyn Kwan, Ph.D., a research scientist with the Kaiser Permanente Northern California Division of Research. "For this reason, we thought that drinking alcohol after a breast cancer diagnosis could increase the risk of a cancer recurrence. But our study found that, overall, drinking alcohol after a breast cancer diagnosis does not impact a patient's prognosis."

Previous studies that looked at alcohol use and breast cancer have had conflicting results. Moreover, most were focused on alcohol use before a breast cancer diagnosis. As a result, there are currently no guidelines for breast cancer survivors on alcohol use. Guidelines for reducing breast cancer risk recommend that women have no more than one alcoholic drink per day.

For their analysis, the research team used data from the Pathways Study, a prospective study of more than 4,500 women diagnosed with invasive breast cancer from 2005 to 2013 at Kaiser Permanente Northern California. It is one of the largest U.S. studies to follow breast cancer survivors to track the relationship between lifestyle changes and outcomes.

"After a breast cancer diagnosis, patients are often focused on making lifestyle changes that could help them live longer," said senior author Lawrence H. Kushi, ScD, a research scientist at the Division of Research who co-leads the Pathways Study.

"Many breast cancer patients have questions about whether drinking alcoholic beverages could lead to breast cancer recurrence. The aim of our study is to provide breast cancer survivors and their physicians with information that can help them make decisions that will improve both their quantity and quality of life."

The new study included more than 3,600 women who had completed a questionnaire about their alcohol use when they entered the Pathways Study at the time of their diagnosis and again 6 months later. Over the next 11 years, 524 women had a breast cancer recurrence and 834 women in the study died—369 from breast cancer, 314 from cardiovascular disease, and 151 from other health problems.

The researchers hope their findings will help clinicians provide accurate information to breast cancer survivors who want to know what lifestyle changes they can make to improve their outcomes.