Personal choices may sway mammography

Primary care physicians who raise the subject of breast cancer screening with their patients may discover that they approach this decision from a different perspective.

Primary care physicians who raise the subject of mammography may discover that they approach decision making about the screening test from a different perspective than their patients.

While breast cancer risk may be elevated due to genetics or family history, most women are considered to be at average risk. But that does not make these conversations any easier for time-pressed physicians and worried patients, given the fears surrounding breast cancer, which takes nearly 44,000 lives in the U.S. each year. Legislation in at least three dozen states has complicated these discussions, requiring women with dense breast tissue to be notified that they're at higher risk for cancer and may want to consider additional testing.

ACP guidance recommends that physicians should start discussing mammography with average-risk women at age 40 years Image by Lordn
ACP guidance recommends that physicians should start discussing mammography with average-risk women at age 40 years. Image by Lordn

Meanwhile, the guidance provided by breast screening centers often does not align with most nonspecialty guidelines, which recommend screening average-risk women annually or biennially starting at age 50 years and note that decisions about starting at age 40 years, when harms generally outweigh benefits, should be made individually after discussion between a patient and her doctor. One recent analysis published in May in JAMA Internal Medicine looked at the mammography guidance posted on the websites of 606 breast cancer centers. Among those 429 centers that provided a starting age and a screening interval, 81% advised annual screening starting at age 40 years.

“The imaging centers often do all of the promotion and follow-up messages out to individuals, and almost in some ways take it out of the hands of the primary care physician,” said Timothy J. Wilt, MD, MPH, MACP, a professor of medicine at the Minneapolis VA Health Care System and one of the authors of ACP's clinical guidance statement for breast screening of average-risk women, published April 16, 2019, in Annals of Internal Medicine. “It's a challenge because it sends mixed messages to our patients.”

Researchers are still trying to sort out some uncertainties about mammography, including at what age screening can be halted and whether a woman's breast density alters the screening calculus. A recent study published March 17, 2020, in Annals of Internal Medicine found that older women may stop mammography without much additional risk. The analysis, which used observational data to emulate a target study, found that continued screening in women ages 70 to 74 years saved one life for every 1,000 women and didn't make any mortality difference in women ages 75 years and older.

These physician-patient discussions and decisions remain highly personalized, said Louise Walter, MD, FACP, chief of the division of geriatrics at the University of California, San Francisco, and the San Francisco VA Health Care System. For instance, if a patient insists on mammograms annually well into her 70s and beyond, she might be a suitable candidate for the test if she understands the potential downsides, such as false positives and overdiagnosis, and appears to be in robust health.

“If she is a healthy older woman who has 10 years or more,” Dr. Walter said, “then there is still definitely a chance that she could die of breast cancer, and why wouldn't a mammogram be potentially helpful for her?”

A risk calculation

Breast cancer prevention can start with younger women as part of routine primary care, said Katrina Armstrong, MD, FACP, physician-in-chief at Massachusetts General Hospital in Boston. Along with educating women about the benefits of reducing or eliminating alcohol consumption and boosting exercise as cancer prevention strategies, physicians also should determine which of their patients might benefit from BRCA gene mutation testing, she said.

A quick screen can be conducted when a woman is in her 30s—Dr. Armstrong typically starts when her patients reach age 35 years—to determine if any of her first- or second-degree relatives have been diagnosed with breast or ovarian cancer and whether she would thus be eligible for testing. “I think we in primary care have not done enough to do that first step,” she said.

Among women who test positive for BRCA or other high-risk gene mutations, breast cancer screening should begin earlier, potentially as early as age 25 years with annual MRIs or annual mammograms if MRI is not available, according to guidelines about genetic mutations and risk-reduction strategies published Jan. 6 in the Journal of the National Comprehensive Cancer Network.

In cases where the woman doesn't have a family cancer history that qualifies her for BRCA testing, the next step would be to conduct a more multifaceted breast cancer risk assessment at age 40 years, such as by using the Gail or the Breast Cancer Surveillance Consortium (BCSC) models, Dr. Armstrong said. That provides a bit more tailored sense of the risk for that individual woman as mammography screening starts to be discussed, she said. If the models show an elevated risk, Dr. Armstrong may recommend that the woman begin screening earlier than age 50 years.

ACP's clinical guidance statement for average-risk women, which reviewed and scored a cross-section of guidelines from medical groups, doesn't recommend that physicians use Gail or other risk calculators, said Dr. Wilt, who also chairs ACP's Clinical Guidelines Committee. None of the assessed guidelines included risk calculators in their recommendations, he said, adding that such calculators were developed to guide possible treatment or lifestyle breast cancer prevention strategies rather than to aid individuals in screening decisions.

According to ACP's guidance statement, physicians should start discussing mammography with average-risk women at age 40 years, including the potential benefits and risks. The potential harms, which include false positives and overdiagnosis, outweigh the benefits in most women ages 40 to 49 years, according to the statement. “Women should be informed participants in personalized decisions about breast cancer screening,” the authors wrote. “Those who do not have a clear preference for screening should not be screened.”

For women ages 50 to 74 years, the statement recommends mammography every other year rather than annually, as there is little to no difference in breast cancer mortality and biennial screening reduces the likelihood of harmful effects. One potential effect cited among all women screened is overdiagnosis, which will occur in about 20% of women diagnosed with breast cancer over a 10-year period, the authors wrote. Thus, they are “likely overtreated, meaning that they would not be bothered by or die of breast cancer if not diagnosed or treated, would not receive benefit, and would only experience harm.”

Can average-risk women be offered more personalized guidance than the existing one-size-fits-all approach? An ongoing U.S. study, called WISDOM (Women Informed to Screen Depending On Measures of risk), is trying to find out. Researchers plan to enroll 100,000 women and compare outcomes between those who got annual mammograms and those whose screening regimen was tailored based on a risk assessment. (No participant will be screened less frequently than what is recommended by the U.S. Preventive Services Task Force [USPSTF].) Participants who choose to be randomized—some women may opt to select their screening approach and thus will be part of an observational group—will be monitored for biopsies and cancers that are stage IIB or higher.

To assess a woman's risk, the study uses the BCSC model, which incorporates a woman's breast density, along with other elements, including race/ethnicity and family history. Researchers are still striving to determine why a woman with dense breasts has an elevated breast cancer risk, Dr. Armstrong said. Two possibilities are that malignancies are more difficult to detect in denser tissue or that density may be an independent risk factor, she said.

Among seven medical groups, the American College of Radiology (ACR) was the only one to recommend additional testing along with mammography in women with dense breasts, according to a summary of breast cancer screening guidelines compiled by the CDC in September 2020. The ACR recommends a breast MRI as well, or an ultrasound in women who cannot undergo MRI.

But there's a catch-22 for women who care about breast density, given that the USPSTF guidelines don't recommend starting mammography until age 50 years, said Ya-Chen Tina Shih, PhD, a professor of health economics in the department of health services research at the University of Texas MD Anderson Cancer Center in Houston.

“What if you have high density [breasts], but then you won't know that until you reach age 50?” Dr. Shih asked. “Maybe having the information earlier starting with a baseline screening at age 40 would help” in guiding women's screening decisions, she said.

In a modeling study published in the May Annals of Internal Medicine, Dr. Shih and her colleagues looked at seven different screening strategies. The analysis found that the most cost-effective approach to reduce breast cancer deaths would be if women got a baseline mammogram at age 40 years and, if they had dense breasts, started screening annually, with the other group screening biennially from ages 50 to 75 years moving forward. But that strategy also would result in the most lifetime screening mammograms along with higher rates of false positives and overdiagnosis, the authors wrote.

Weighing pros and cons

While treatment has improved for many types of malignancies, and particularly of the breast, the entire subject of cancer remains emotionally fraught, said Anand Habib, MD, MPhil, an internal medicine resident at the University of California, San Francisco, and first author on a May editorial, also published in JAMA Internal Medicine, that critiqued the mammography guidance provided by the breast cancer centers. Dr. Habib cited a survey published in 2018 in the Journal of Oncology Practice, which found that 45% of 420 adults surveyed agreed with this statement: “Most of the time cancer is a rapidly terminal disease.” In 2007, 61% of respondents agreed.

Given how frequently breast cancer is diagnosed, Dr. Habib said, “every individual probably has a family member, a friend, a neighbor, a colleague who was affected by breast cancer at some point in her lifetime. That already primes individuals to think, ‘Oh, my gosh, I don't want to miss something.’”

He suggested approaching the conversation with open-ended questions, such as “What are your thoughts around screening? What have you heard from friends and family? Do you have a preexisting preference?,” and then at some point offering, “Might I provide a recommendation?”

Dr. Wilt suggested that physicians start talking to women once they reach their 40th birthday, or even slightly before, about the risks and benefits of mammography. He typically stays away from a litany of statistics to keep his patients' eyes from glazing over. Instead, he provides the topline message, as he described it: “In your situation, this test is unlikely to provide benefits that outweigh the harms.”

Along with explaining the higher likelihood of false positives and related testing before age 50 years, Dr. Wilt talks about the potential for overdiagnosis. “That's a hard one for most people to understand,” he said, “that the more we look, the more we find things that may not be of any problem to an individual.”

Dr. Armstrong also alerts her patients that more frequent screening may result in more false positives and related testing. But in her experience, an abnormal finding—even when a biopsy is needed—may leave patients more committed to mammography moving forward.

“Almost universally they feel this incredible sense of gratitude, that they were found to have this [abnormality], but it was not cancer,” she said. “Nobody feels happier than the day they're told they don't have cancer.”

Since randomized mammography studies didn't include women in their late 70s or older, it has been less clear what physicians should advise patients in that age group, Dr. Walter said. ACP's guidance statement recommends considering stopping mammography once a woman reaches age 75 years, or if her life expectancy is anticipated to be less than 10 years. A recently published consensus statement by the International Society of Geriatric Oncology, which Dr. Walter helped author and which focused on breast cancer survivors only, also tied guidance to life expectancy.

Those consensus guidelines, published in the April JAMA Oncology, recommended discontinuing screening for breast cancer survivors with a life expectancy of less than five years, including those with a history of high-risk breast cancers. Physicians should also consider advising against mammography if a patient's life expectancy is projected to be between five and 10 years, according to the guidelines.

These are broad recommendations, and physicians should still personalize the conversation to each patient, Dr. Walter said. In terms of projecting life expectancy, UCSF offers a calculator to provide rough averages, she said. (The site also offers a breast cancer screening aid.) Too often, the life expectancy of healthy older adults may be underestimated, she said. “If you make it to 80, you have close to a 50:50 chance of making it to 90.”

Ideally, physicians should start raising the possibility of one day stopping the screening test as their female patients approach their mid-70s, Dr. Walter said. She suggests framing the conversation in terms of shifting health care priorities, rather than discussing potential life expectancy. For example, a physician could say, “I really believe that getting a mammogram would be distracting right now. What we need to focus on is your heart failure or your memory problems or your kidney problems.”

Dr. Armstrong adopts a similar approach. Some older patients, she said, are more comfortable with continuing the annual test, which is “a reasonable decision.” But, she added, “Many patients, if they are told that there's no evidence that it benefits them, are really pretty happy to stop screening. I wouldn't say that people look to their mammography date as the favorite date in their year.”