ALCOHOL AND BREAST CANCER

December 11, 2009 (San Antonio, Texas) — Clinicians need to provide a "nuanced message" about alcohol consumption to women with early-stage breast cancer, said a presenter here at the 32nd Annual San Antonio Breast Cancer Symposium.

The message needs to be nuanced because, as a new study presented here showed, light consumption (fewer than 3 drinks per week) did not increase the risk for breast cancer recurrence in early-stage disease.

However, moderate to heavy consumption of alcoholic beverages (3 or 4 drinks per week, or more) was associated with a 1.3-fold increased risk for breast cancer recurrence and a 1.5-fold increase in breast cancer deaths, according to the study.

These results must be weighed against past research that shows that "moderate alcohol consumption" decreases the risk for cardiovascular disease, said epidemiologist Michelle D. Holmes, MD, DrPH, from Harvard University in Boston.

"Many women live a long time with early breast cancer, and alcohol consumption may decrease the risk of heart disease [during that time]," said Dr. Holmes, who acted as a discussant of the study on alcohol use and breast cancer disease recurrence.

Dr. Holmes also noted that the new study did not show that alcohol consumption was associated with a higher risk for death from all causes.

The lead author of this study was Marilyn L. Kwan, PhD, from Kaiser Permanente in Oakland, California.

Dr. Kwan and her Kaiser colleagues looked at the association between alcohol intake and cancer recurrence and mortality in the Life After Cancer Epidemiology (LACE) Study, a prospective cohort study of 1897 early-stage breast cancer survivors.

After 8 years of follow-up, the researchers found 349 breast cancer recurrences (18%) and 332 deaths (17%). A little more than half (57%) of the deaths were from breast cancer.

Among the group that drank 3 or 4 drinks per week, or more, the increased risk for recurrence was pronounced in postmenopausal (hazard ratio [HR], 1.51; 95% confidence interval [CI], 1.20 - 2.54) and overweight/obese (HR, 1.58; 95% CI, 1.07 - 2.35) women.

Dr. Kwan said that, on the basis of these findings, "women previously diagnosed with breast cancer should consider limiting their consumption of alcohol to less than 3 drinks per week, especially women who are postmenopausal and overweight or obese."

Dr. Holmes agreed that obese women with breast cancer should be careful about drinking alcohol and that they might have "particularly bad" survival outcomes if they do.

As for a possible reason for the effect of alcohol on breast cancer recurrence, Dr. Kwan noted that "alcohol increases estrogen metabolism and circulating estrogen."

What's Been Found Before

Previous research has shown consistently that the regular consumption of alcohol is associated with an increased risk of developing breast cancer, said both Dr. Kwan and Dr. Holmes.

"There's about a 10% increased risk for each drink consumed per day," summarized Dr. Holmes.

There are far fewer studies about the role of alcohol in patient prognosis and survival among women already diagnosed with breast cancer, noted Dr. Holmes.

And in those studies, there are "mixed" results as to whether there is an association between alcohol and overall survival. Eight studies showed no association, 1 study showed decreased mortality, and 1 study showed increased mortality, Dr. Holmes tabulated.

The advantage of the LACE study is that the data are from Kaiser Permanente, a health maintenance organization, which means that the study has highly accurate information on recurrence.

Study Details

The great majority of the 1897 women participating in the LACE study come from the Kaiser Permanente Northern California Cancer Registry. The women in this registry were diagnosed from 1997 to 2000 with early-stage primary breast cancer (stage I ≥1 cm, stage II, or stage IIIA) and were 18 to 70 years of age at study enrollment.

Recurrence was defined as local, regional, and distant disease, new contralateral breast cancers, and breast cancer death if no previous recurrence was recorded.

Information on alcohol intake (wine, beer, liquor) during the 12 months after enrollment was obtained from a validated food frequency questionnaire.

Among drinkers (50% of the study population), wine was most popular (90%), followed by liquor/spirits (43%) and then beer (3%).

Compared with nondrinkers, drinkers in the study were younger, predominantly white, more educated, and more likely to be smokers and former smokers. There was no difference by menopausal status, lymph node status, or tamoxifen use between the drinkers and nondrinkers.

Dr. Kwan called for more research in this area, which is such a hot topic and has led some breast cancer commentators to call for a ban on the use of pink ribbons on alcoholic products.

"Considering the few studies that have addressed alcohol and its influence on breast cancer prognosis, and that the increased risk of recurrence was observed in only some subgroups, our results should be confirmed in other prospective studies. However, these results can help women make a more informed decision about lifestyle choices after a diagnosis of breast cancer," said Dr. Kwan in a press statement.

The study was funded by the National Cancer Institute and the Utah Cancer Registry. The authors have disclosed no relevant financial relationships.

32nd Annual San Antonio Breast Cancer Symposium (SABCS): Abstract 17. Presented December 10, 2009.