‘No right answer’ to questions about optimal time for breast cancer screening initiation
Physician recommendations about the optimal time to initiate and discontinue breast cancer screening often continue to conflict with guidance from professional societies and independent experts.
Most primary care physicians recommend mammography screening for women beginning at age 40 years, even though guidelines from the American Cancer Society and U.S. Preventive Services Task Force (USPSTF) support a personalized approach toward screening for women in this age group, according to a research letter published in JAMA Internal Medicine.
Physician recommendations are one of the most important factors in a patient’s decision to undergo or forgo screening; hence, consensus is desired regarding when and how often to screen for breast cancer.
Archana Radhakrishnan, MD, clinical research fellow in the division of general internal medicine at Johns Hopkins University, and colleagues used data from the Breast Cancer Social Networks study — a national survey of PCPs — to determine whether physicians’ specialties or their organizational trust appeared associated with their breast cancer screening recommendations.
The bivariate analyses included 871 randomly selected PCPs (73.9%) and gynecologists (26.1%) who cared for women aged 40 years or older.
The survey asked participants whether they typically recommended routine screening mammograms to women in three age groups — 40 to 44 years; 45 to 49 years; and 75 years or older — with no family history of breast cancer and no prior breast issues.
Results showed 81% of physicians recommended mammography screening for women aged 40 to 44 years; 88% recommended it to women aged 45 to 49 years; and 67% recommended it to women aged 75 years or older.
Gynecologists appeared more likely than PCPs to recommend screening to women of all age groups (P < .001).
The survey showed a relatively even split with regard to which organization’s guidelines the survey respondents trusted most; 26% indicated they most trusted the American Congress of Obstetricians and Gynecologists (ACOG), 23.8% selected the American Cancer Society and 22.9% favored USPSTF guidelines.
“The results provide an important benchmark as guidelines continue evolving, and [they] underscore the need to delineate barriers and facilitators to implementing guidelines in clinical practice,” Radhakrishnan and colleagues wrote.
HemOnc Today spoke with experts on both sides of the debate about the potential advantages and disadvantages of early initiation of mammography screening.
Although the USPSTF has determined the benefits of mammography outweigh the risks for women aged 40 to 49 years, the difference is so subtle that it is important that women make their own choice about whether to be screened, according to George F. Sawaya, MD, professor of obstetrics, gynecology and reproductive sciences at University of California, San Francisco.
In addition, women in their early 40s must be aware of the likelihood of various outcomes, including the potential for false-positive results, Sawaya said.
In a debate at this year’s ACOG Annual Clinical and Scientific Meeting, Sawaya argued in favor of USPSTF guidelines that recommend biennial screening for women aged 50 to 74 years and assign a “C” grade — meaning decisions should be based on clinicians’ professional judgment and patient preferences — to a recommendation of screening for women aged 40 to 49 years.
“The process the task force uses to establish these recommendations is detailed, transparent and laborious,” Sawaya told HemOnc Today. “In considering the age to begin screening and the periodicity of screening, the task force believes that the best balance is beginning screening at age 50 and repeating screening every 2 years until the age of 74.”
The task force assigned a “B” grade — characterized as a recommendation of the service — to biennial screening for those aged 50 to 74 years because the task force believes that the net benefit is of a moderate magnitude, Sawaya said.
“Both of these are positive recommendations,” Sawaya said. “For the ‘C’ grade recommendation, the task force believes that women who place a higher value on their potential benefits than the potential harms may choose to begin biennial screening between the ages of 40 and 49. I have a great deal of confidence in the process undertaken by the USPSTF, and I believe it to be reasonable for physicians to look at the USPSTF guidelines for a variety of conditions as their primary source for recommendations.”
Earlier screening saves lives
Annual screening saves the most lives in every age group — including those in their 40s — and that should be physicians’ primary focus, according to Debra Monticciolo, MD, chair of the American College of Radiology Breast Imaging Commission.
“[Although] decreasing mortality from breast cancer is the main goal, there are additional benefits of screening, because screening-detected tumors tend to be smaller and are easier to treat,” Monticciolo told HemOnc Today.
Screening provides opportunity for less aggressive surgery and oncologic therapies, she said.
“A woman who wants to maximize the benefits of screening should start at age 40 and continue annually,” Monticciolo added. “This is the best way to reduce mortality and morbidity from breast cancer.”
A small amount of overdiagnosis — or the detection of early breast cancers that may never pose a threat — likely occurs, but it cannot be measured directly, Monticciolo said.
“All that we have are estimates, and these are based on assumptions that vary among studies,” she said.
Studies that correctly account for lead time and underlying incidence trends revealed overdiagnosis rates between 1% and 10%, Monticciolo said.
“It should be made clear that breast cancers look suspicious on mammography — even those that may be part of overdiagnosis,” she said. “Waiting ... to start screening at age 50 instead of age 40 will not change this. These tumors will still be present — although larger — at age 50. We have shown that breast cancer does not spontaneously regress. Invasive tumors do not go away without treatment.”
A relatively small number of overdiagnoses should not be used to determine the appropriate age to start screening, or the interval at which individuals are screened, Monticciolo said.
“We do not know which tumors are the overdiagnosed lesions, so we cannot use this to inform the screening recommendation,” she said. “The only way to not overdiagnose is to not screen at all, which we definitely do not want to do.”
Search for common ground
Despite the variations between recommendations issued by professional societies and independent panels, the general consensus among experts is that mammography ultimately saves lives.
“All major guidelines are similar with regard to the age to begin screening,” Sawaya said. “The major differences between the USPSTF and other major medical groups is how often screening should be performed — annually or biannually. There is no right answer here, only different ways to put together and view the pieces of a complex problem, and we as physicians have to be careful in doing so. Screening by definition is trying to make well people better in the future, but we do not want to harm them inordinately in this pursuit.”
Monticciolo agreed that the professional societies and the USPSTF are united in the belief that mammography substantially reduces breast cancer mortality.
“However, the difference exists in the way the USPSTF advises women of the risks and harms of screening at a younger age and more frequently,” Monticciolo said. “[Although] there are always risks to screening, I do not think that dying from breast cancer is on the same scale as having anxiety, getting recalled to have extra images taken or undergoing minimally invasive needle biopsy for what turns out to be a benign biopsy.
“Physicians need to know the facts and think about the patient’s best interest,” she added. “Women need to understand that mammography screening is associated with more benefits than harms, including decreasing their chance of dying of breast cancer.” – by Jennifer Southall
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For more information:
Debra Monticciolo, MD, can be reached at Scott & White Medical Center, Department of Radiology, 2401 S. 31st St., Temple, TX 76508; email: firstname.lastname@example.org.
George F. Sawaya, MD, can be reached at The University of California, San Francisco, 550 16th St., Floor 7, San Francisco, CA 94143; email: email@example.com.
Disclosure: Monticciolo and Sawaya report no relevant financial disclosures.