Responding to Objections
Not surprisingly, the task force has heard objections to its draft guidelines. The first is that women aged 40-49 years are being denied mammograms, said Michelle Nadler, MD, a medical oncologist at Princess Margaret Cancer Centre in Toronto, Canada. “This [objection] has attained a lot of media coverage, which is unfortunate, because people who have not read the guidelines may believe this is true. The guidelines clearly state that an eligible, informed woman of this age group who wants a screening mammogram should receive one.”
The second commonly heard objection is that the task force is overestimating the harms of screening, such as anxiety and overdiagnosis, she said. But an outcome of “anxiety” was not factored into the guideline. Overdiagnosis was calculated on the basis of the literature, and estimates were converted to a common denominator so that they could be compared, said Dr. Nadler. The same was true of benefits.
Another objection was that screening could mean less need for chemotherapy or full axillary dissection, Dr. Nadler said. However, the task force did not find any primary studies that evaluated these outcomes.
Critics also said that the recommendations do not account for racial or ethnic variations. Although more research is likely needed in this area, “the task force states that individuals should be informed of all of their breast cancer risk factors, including race/ethnicity, and that this should be factored into decisions about screening,” said Dr. Nadler.
“I was very surprised that the task force was accused by some parties of paternalism,” added René Wittmer, MD, adjunct clinical professor of family medicine at the University of Montreal and chair of Choosing Wisely Quebec, Montreal, Canada. “In my opinion, the importance they place on shared decision-making is contrary to medical paternalism and aims to empower women to make a decision that fits with their values and preferences.”
Nevertheless, the inclusion of modeling studies and observational trials “may cause the potential benefits to be amplified, compared with what is seen in randomized controlled trials,” he said in an interview.
Decision Aids Help
Once the guidelines are finalized, decision aids will be available to patients and providers to help guide screening discussions, said Dr. Nadler. “Primary care providers need to be aware of an individual’s personal risk factors for breast cancer to know if they are at average, above average, or high lifetime risk of breast cancer. These guidelines do not apply to those with > 20% lifetime risk of breast cancer.”
“The standards for risk communication are in absolute numbers over a common denominator,” she noted. “This is how primary care providers discuss other important primary care topics like smoking cessation, cardiovascular disease (and decisions about statin medications), and osteoporosis risk. These same standards should apply for breast cancer screening.”
Furthermore, she said, providers “should be aware that individuals from marginalized communities may benefit from more than one conversation until they are able to make a decision about screening that is right for them.”
“There is good evidence showing that most advances we’ve seen in breast cancer outcomes (ie, reduction in breast cancer mortality) are likely due to improvements in treatment, not screening,” said Dr. Wittmer. “In fact, mortality reductions are seen even in age groups or countries where there is no routine screening. This means that women benefit from advances in treatments, whether they choose to get screened or not.”