Screening guidelines hinge on the belief that mammograms are important, but at what age? Here is where divergence occurs; experts can’t agree on age and frequency.
The U.S. Preventive Services Task Force recommends mammograms every other year, from age 50 through age 74.
The American College of Obstetricians and Gynecologists recommends consideration of beginning mammograms at 40, but starting no later than 50, and continuing until age 75. These can be done every one or two years. They encourage a process of shared decision-making between patient and physician.
Just as important as screening is prevention, whether it is primary, preventing the disease from occurring, or secondary, preventing recurrence. Potential ways of doing this may include lifestyle modifications, such as diet, exercise, obesity treatment and normalizing cholesterol levels.
Additionally, although results are mixed, it seems that bisphosphonates do not reduce the risk of breast cancer.
Bisphosphonates include Fosamax (alendronate), Zometa (zoledronic acid) and Boniva (ibandronate) used to treat osteoporosis. Do they have a role in breast cancer prevention? It depends on the population and on study quality.
In a meta-analysis involving two randomized controlled trials, FIT and HORIZON-PFT, results showed no benefit from the use of bisphosphonates in reducing breast cancer risk.
The study population involved 14,000 postmenopausal women from ages 55 to 89 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.
The researchers concluded that the data were not evident for the use of bisphosphonates in primary prevention of invasive breast cancer.
In a previous meta-analysis of two observational studies from the Women’s Health Initiative, results showed that bisphosphonates did indeed reduce the risk of invasive breast cancer in patients by as much as 32 percent.
However, there was an increase in ductal carcinoma in situ (precancer cases) risk that was not explainable. According to the authors, this suggested that bisphosphonates may have an antitumor effect. But not so fast!
The disparity in the above two bisphosphonate studies has to do with trial type. Randomized controlled trials (RCTs) 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.
In an observational trial, exercise reduced breast cancer risk in postmenopausal women significantly. These women exercised moderately; they walked four hours a week over a four-year period. If they exercised previously, but not recently, for instance, five to nine years ago, no benefit was seen.
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 as a prevention method as we do screenings.
Western vs. Mediterranean diets
A Mediterranean diet may decrease the risk of breast cancer significantly.
In an observational study, results showed that, while the Western diet increases breast cancer risk by 46 percent, the Spanish Mediterranean diet has the inverse effect, decreasing risk by 44 percent.
The effect of the Mediterranean diet was even more powerful in triple-negative tumors, which tend to be difficult to treat. The authors concluded that diets rich in fruits, vegetables, beans, nuts and oily fish were potentially beneficial.
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 a Mediterranean diet and modest exercise, we may be able to accelerate the trend toward a lower breast cancer incidence.