Breast Cancer

The relationship of breast cancer and alcohol continues to draw considerable commentary in the press. After the Harvard-led Nurses’ Health Study was published in 2011, panic swept over the country. The widely reviewed study concluded that drinking as little as three glasses of wine or other drinks per week increased the risk of breast cancer in women compared to abstainers. The authors admitted that the increased risk for drinkers of light-to-moderate amounts of alcohol was quite small. This was an observational study and cause and effect between alcohol and breast cancer was not linked for certain. The effects of folate intake were not reported although it has been shown that folate is a potential moderator of the effects of alcohol on breast cancer risk. The study’s lead author said, “What I generally tell women is to keep alcohol consumption at a few servings per week.” The International Scientific Forum on Alcohol Research concluded, “An individual will need to weigh the modest risks of light to moderate alcohol use on breast cancer development against the beneficial effects on cardiovascular disease to make the best personal choice regarding alcohol consumption.” Perhaps the words of Richard A. Baxter, M.D., author of Age Gets Better With Wine, are most reasonable, with his remark regarding wine and breast cancer emphasizing to women, “The smart choice favors having a glass of wine with dinner and not stressing over it.”

Moderate Alcohol Consumption and Breast Cancer in Women: From Epidemiology to Mechanisms and Interventions Alc Clin Exp Res 37 (s6) January 2013 The National Institute on Alcohol Abuse and Alcoholism (NIAAA) released this review. The NIAAA said, “Existing epidemiologic evidence supporting the relationship between moderate alcohol consumption and breast cancer risk needs further study.” The NIAAA analyzed recent epidemiologic studies and alcohol and breast cancer. Many of these studies use the selfreporting method (people tend to report less alcohol than they actually consume) and do not consider time course and drinking patterns. Dr. Philip J. Brooks, program officer in the NIAAA Division of Metabolism and Health Effects states the following. “In view of our lack of understanding of how and when alcohol consumption impacts breast cancer risk, and the documented health benefits of moderate alcohol consumption, it is not clear that stopping drinking would benefit the overall health of postmenopausal women who are moderate drinkers. In contrast, based on our understanding of alcohol metabolism, as well as recent epidemiologic data, binge drinking by younger women could increase the risk of breast cancer later in life. Binge drinking is unhealthy for anyone, and the possibility of increasing breast cancer risk is another reason for women in particular to avoid binge drinking.”

Pre-diagnostic Alcohol Consumption and Postmenopausal Breast Cancer Survival: A Prospective Patient Cohort Study Breast Cancer Res Treat 136 (1) November 2012 A German study on 2,522 postmenopausal breast cancer patients aged 50-74 years found that pre-diagnostic alcohol consumption was non-linearly associated with increased breast cancer-specific mortality, and was not associated with overall mortality and breast cancer recurrence. The authors concluded that consumption of alcohol before diagnosis in non-linearly associated with increased breast cancer-specific mortality, but may be associated with decreased risk of mortality due to other causes.

Postdiagnosis Alcohol Consumption and Breast Cancer Prognosis in the After Breast Cancer Pooling Project Cancer Epidemiol, Biomarkers & Prevention 22 January 2013 9,329 breast cancer patients from Kaiser Permanente Northern California were studied. Alcohol intake was assessed at cohort entry using a questionnaire. Regular alcohol consumption (6 g per day or about 1/2 standard drink a day) was not associated with breast cancer recurrence and total mortality overall. Cohorts with high amounts of alcohol intake (24 g per day or about 2 standard drinks per day) were 34% more likely to have recurrence compared to abstainers. Recurrence risk was elevated in postmenopausal women. The association between alcohol intake and recurrence may depend on menopausal status at breast cancer diagnosis with an increased risk of recurrence (19%) in postmenopausal women who regularly consumed alcohol. Alcohol intake was not related to mortality.

Alcohol Consumption, Body Mass Index and Breast Cancer Prognosis: Results from the Search Study Presentation at the 8th NCRI Cancer Conference in Liverpool, England November 4-7, 2012. The study looked at 13,525 women diagnosed with breast cancer and recorded the women’s weekly alcohol intake. Women who drank three and a half small glasses of wine each week were 10 percent more likely to survive breast cancer than nondrinkers. Women who drank seven small glasses a week upped their survival rate by 20 percent over women who did not drink. Women were more likely to survive breast cancer with increasing current alcohol consumption with a 2% reduction in risk per unit of alcohol consumed per week. A woman with breast cancer has a 20 percent chance of dying within 10 years but researchers said this was reduced to 18 percent if she drank seven units a week and 17 percent with 14 units. The benefit was slightly stronger for women with estrogen-receptor negative breast cancers. There are no specific protocols for drinking alcohol in patients diagnosed with breast cancer but many women quit drinking. This study suggests it is reasonable to enjoy an occasional drink after breast cancer diagnosis since the study found that alcohol was only beneficial after the diagnosis of breast cancer had been made. The study also found that the prognosis of breast cancer was poorer in women who were overweight.

Alcohol Consumption Suppresses Mammary Tumor Metastasis in a Syngeneic Tumor Transplantation Model Breast Cancer Res and Treat 136 (3) December 2012 A study on mice found that alcohol consumption does not exacerbate tumor metastasis, moderate drinking suggests a reduction in tumor spread but is not statistically significant, and high alcohol consumption reduces tumor spread.

Effect of Resveratrol on the Metastasis of 4T1 Mouse Breast Cancer Cells In Vitro and In Vivo Nutrition Research and Practice 6 (4) August 2012 This Korean animal study found the efficacy of resveratrol in preventing metastasis in mice with breast cancer in vitro and in vivo was dose responsive meaning a high dose provided better protection. This is the first report that oral administration of resveratrol inhibits the metastasis of 4T1 cells to the lungs in a murine model of experimentally induced cancer. Suggests that possibly taking resveratrol supplements may help prevent or treat breast cancer and prevent the disease from progressing to an advanced stage. Studies on humans need to be done to confirm these findings.

Alcohol Consumption and Breast Cancer Risk Among Postmenopausal Women Following the Cessation of Hormone Therapy Use: The California Teachers Study Cancer Epidemiol, Biomarkers & Prevention 21 November, 2012 An analysis of more than 40,000 postmenopausal women showed an increase in risk of breast cancer among alcohol consumers of more than 1.5 to 2 drinks per day who were currently on hormone therapy but not among those who were ex-users of hormone therapy. There was a 60 percent greater risk for women who drink while undergoing hormone therapy compared with women who drink responsibly and are not on hormone replacement. The study concluded that concurrent exposure to hormone therapy and alcohol has a substantial adverse impact on breast cancer risk that is reduced after hormone therapy cessation. The study probably offers little if any cause for concern to women who are on natural or bioidentical hormones and consume alcohol (most women in this study received medroxyprogesterone acetate rather than natural or bioidentical progesterone).

Epidemiology and Pathophysiology of Alcohol and Breast Cancer: Update 2012 Alcohol and Alcoholism 47 (3) May/June 2012 A meta-analysis of 113 studies of the relationship of breast cancer risk and alcohol consumption. There was a 4% increase in risk of breast cancer at intakes of up to one alcoholic drink per day compared to nondrinkers. Heavy drinking, defined as three or more drinks per day, is associated with a 40% to 50% increased relative risk of breast cancer compared with not drinking at all. The authors estimate that 1-2% of breast cancers in Europe and North American are due to light drinking alone. The mechanisms involved are not clearly established and probably diverse. The authors of the study conclude that there is a positive doseresponse relation between alcohol drinking and the risk of breast cancer. An increase in estrogen levels from alcohol seems to be the physiologic mechanism most commonly suggested for the increase in risk of breast cancer, but other possibilities include acetaldehyde effects and oxidative stress. Even among women with an average of only about one drink per day there is an increased risk. However, the authors did not discuss the protective effect of dietary folate and the benefits of moderate drinking on reducing the risk of cardiovascular disease which is a much more common cause of death than breast cancer.

Intake of Alcohol and Folate During Adolescence and Risk of Proliferative Benign Breast Disease Pediatrics 129 (5) May 2012 This study followed 29,000 females from the Nurses Health Study. Women were free of cancer and proliferative benign breast disease (BDD) at the start of the study. The cohorts answered questions on alcohol and folate intake. Average followup was ten years. For each 10 g of alcohol (defined as one drink in this study) consumed each day, the risk of developing non-cancerous cells and lesions (BDD) increased 15 percent. Folate intake had no effect on BDD. Not everyone with BDD goes on to develop breast cancer but the findings are of concern. The study did not prove a cause-and-effect relationship although it uncovered an association between adolescent alcohol use and BDD.

Alcohol, Genetics and Risk of Breast Cancer in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial Breast Cancer Res Treat 133 (2) June 2012 Subjects were women aged 55-74 at baseline. A self-administered food frequency questionnaire inquired about the frequency and usual serving size of beer, wine and liquor. The study included 1,041 incident breast cancer cases and 1,070 controls. In comparison to non drinkers, the intake of any alcohol significantly increased the risk of breast cancer, and this risk increased with each category of daily alcohol intake for women. For those women with the ADH1B gene, there were statistically significant associations between all levels of alcohol intake and risk of breast cancer. For women with the GA or AA genotype, there no significant associations between alcohol intake and risk of breast cancer. The authors concluded that alcohol intake, genes involved in alcohol metabolism and their interaction increase the risk of breast cancer in post-menopausal women. This information could be useful for primary care providers to personalize information about breast cancer risk reduction. (Note, the genetics involved in breast cancer are far too complicated to explain here. Suffice it say, individual women alcohol drinkers have different genetic makeups that are determinable by testing, and can influence their risk of breast cancer.)