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Alcohol and Breast Cancer Outcomes
Robert S. Mocharnuk, MD:
This expert analysis discussion will focus on clinically significant abstracts pertaining to breast cancer prognosis and prediction of response to breast cancer treatment, all of which were presented at the 2009 Annual AACR-CTRC San Antonio Breast Cancer Symposium. The outcomes of these studies have provided us further insights in understanding the biology of breast cancer and understanding whether patients will respond to treatments, both important factors in improving overall outcomes. We will begin by discussing several studies that focused on breast cancer risk factors.
William J. Gradishar, MD, FACP:
Kwan and colleagues[1] conducted a nonrandomized analysis of the prospective LACE cohort study[2] and found that consuming at least 3-4 alcoholic drinks (beer, wine, spirits) per week was independently associated with an increased risk of recurrence and breast cancer–related death in women previously diagnosed with early-stage breast cancer (
Capsule Summary). In total, 1897 patients were included in the analysis. Alcohol consumption of ≥ 6.0 g/day was associated with a 34% increased risk of recurrence compared with a consumption of 0 g/day (
P = .04).During a mean follow-up of 3-4 years, the researchers also found that that the association between alcohol consumption and recurrence was strongest among postmenopausal women and overweight/obese women, although no significant association between alcohol consumption and overall risk of death was observed. The findings indicate that women, particularly if postmenopausal or overweight/obese, should limit alcohol consumption following breast cancer diagnosis.
This is one of many reports in the literature highlighting a relationship between alcohol intake and increased risk or worse outcomes in breast cancer. The important take-home message from this study is that the findings are interesting, but this type of study is exceedingly difficult to perform in terms of trying to obtain accurate information and account for confounders that could influence risk of recurrence. Clearly, there is always a risk of under-reporting, both with respect to alcohol intake and dietary factors. Notably, the amount of alcohol that was correlated with an increased risk of recurrence was quite modest, which may reflect under-reporting in the study. In addition, confounders could have influenced the results. Therefore, in my opinion, this study does not change clinical practice or how we might counsel patients; however, it does suggest that, as with other things, moderation is key.
Paul E. Goss, MD, PhD, FRCPC, FRCP:
I agree with Dr. Gradishar. The investigators reported a hazard ratio of 1.42, which reflects the increased risk between an intake of < 0.5 g vs > 6.0 g. This is a comparison between the very upper end of a range vs the lowest, and only a modest increase in the hazard ratio for risk was observed. There are many lifestyle risk factors that increase the risk of breast cancer from a hazard ratio of between 1.0 and 2.0 in this type of study. Alcohol intake is only one of them. I agree that the clinical implications of these findings are unclear given the potential confounders and statistical variables that may be present in this study. These data are interesting, but should not impact clinical practice at this point.
Daniel F. Hayes, MD:
It seems we all agree that these findings are plausible and consistent with previous findings.We could also agree that these findings may help support a biological mechanism between alcohol and breast cancer—specifically, many believe that the link is probably related to estrogen metabolism, although this has been hard to prove. However, a third point is whether the findings should influence clinical practice. This is the kind of study that will prompt patients to ask, “Should I quit drinking?” I tell my patients that they should not quit drinking because of the study, but that drinking in moderation is appropriate relative to a variety of health issues, including breast cancer outcomes. A glass of wine occasionally is fine, although of course heavy alcohol use has many health consequences including those related to breast cancer outcomes and should be avoided.
Hopeful