Medical Compass: Beyond pink ribbons – Reducing breast cancer risk
Understand your risk profile and design a screening plan with your physician
By David Dunaief, M.D.
Get out your pink attire, because October is Breast Cancer Awareness Month.
The most common cancer diagnosed in U.S. women, an estimated 30 percent of 2021 cancer diagnoses in women will be breast cancer (1). Of these, 85 percent of cases occur in those with no family history of the disease, and 85 percent of new cases will be invasive breast cancer.
A primary objective of raising awareness is to promote screening for early detection. While screening is crucial, prevention should be just as important, including primary prevention, preventing the disease from occurring, and secondary prevention, preventing recurrence.
Here, we will discuss current screening recommendations, along with tools to lower your risk.
At what age and how often should we be screened?
Here is where divergence occurs; experts don’t agree on age and frequency. The U.S. Preventive Services Task Force currently recommends mammograms every other year, from age 50 through age 74, with the option of beginning as early as age 40 for those with significant risk (2). It’s important to note that these guidelines, published in 2016, are currently being refined and are pending publication.
The American College of Obstetricians and Gynecologists recommends consideration of beginning annual or biennial mammograms at 40, but starting no later than 50, and continuing until age 75. They encourage a process of shared decision-making between patient and physician to determine age and frequency of exams, including whether to continue after age 75 (3).
The American Cancer Society’s physician guidelines are to offer a mammogram beginning at age 40 and recommend annual or biennial exams from 45 to 54, with biennial exams after 55 until life expectancy is less than 10 years (4).
While the recommendations may seem nuanced, it’s important to consult with your physician to determine your risk profile and plan or revise your regular screening schedule accordingly.
Do bisphosphonates help?
Bisphosphonates include Fosamax (alendronate), Zometa (zoledronic acid) and Boniva (ibandronate) and are used to treat osteoporosis. Do they have a role in breast cancer prevention? It depends on the population, and it depends on study quality.
In a meta-analysis involving two randomized controlled trials (RCTs), FIT and HORIZON-PFT, results showed no benefit from the use of bisphosphonates in reducing breast cancer risk (5). The study population involved 14,000 postmenopausal women from ages 55 to 89 women who had osteoporosis, but who did not have a personal history of breast cancer. In other words, the bisphosphonates were being used for primary prevention.
In a more recent meta-analysis of 10 studies with over 950,000 total participants, results showed that bisphosphonates did indeed reduce the risk of primary breast cancer in patients by as much as 12 percent (6). However, when the researchers dug more deeply into the studies, they found inconsistencies in the results between observational and case-control trials versus RCTs, along with an indication that longer-term use of bisphosphonates is more likely to be protective than use of less than one year.
Randomized controlled trials are better designed than observational trials. Therefore, it is more likely that bisphosphonates do not work in reducing breast cancer risk in patients without a history of breast cancer or, in other words, in primary prevention.
A Lancet metanalysis focused on breast cancer recurrence in distant locations, including bone, and survival outcomes did find benefits for postmenopausal women (7). A good synopsis of the research can be found at cancer.org.
How much exercise?
We know exercise is important in diseases and breast cancer is no exception. In an observational trial, exercise reduced breast cancer risk in postmenopausal women significantly (8). These women exercised moderately; they walked four hours a week over a four-year period. If they exercised previously, five to nine years ago, but not recently, no benefit was seen. The researchers stressed that it is never too late to begin exercise.
Only about one-third of women get the recommended level of exercise every week: 30 minutes for five days a week. Once diagnosed with breast cancer, women tend to exercise less, not more. We need to expend as much energy and resources emphasizing exercise for prevention as we do screenings.
What about soy?
Contrary to popular belief, soy may be beneficial in reducing breast cancer risk. In a meta-analysis, those who consumed more soy saw a significant reduction in breast cancer compared to those who consumed less (9). There was a dose-response curve among three groups: high intake of >20 mg per day, moderate intake of 10 mg and low intake of <5 mg.
Those in the highest group had a 29 percent reduced risk, and those in the moderate group had a 12 percent reduced risk when compared to those who consumed the least. In addition, higher soy intake has been associated with reduced recurrence and increased survival for those previously diagnosed with breast cancer (10). The benefit from soy is thought to come from isoflavones, plant-rich nutrients.
Hooray for Breast Cancer Awareness Month stressing the importance of mammography and breast self-exams. However, we need to give significantly more attention to prevention of breast cancer and its recurrence. Through potentially more soy intake, as well as a Mediterranean diet and modest exercise, we may be able to accelerate the trend toward a lower breast cancer incidence.
(1) breastcancer.org. (2) uspreventiveservicestaskforce.org. (3) acog.org. (4) cancer.org. (5) JAMA Intern Med. 2014;174(10):1550-1557. (6) Clin Epidemiol. 2019; 11: 593–603. (7) Lancet. 2015 Jul 23. (8) Cancer Epidemiol Biomarkers Prev. 2014 Sep;23(9):1893-902. (9) Br J Cancer. 2008; 98:9-14. (10) JAMA. 2009 Dec 9; 302(22): 2437–2443.
Dr. David Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, visit www.medicalcompassmd.com.