The controversy over breast cancer screening centered largely on a handful of terms and concepts that were overlooked, ignored, misunderstood, or misinterpreted, according to the authors of a commentary on the issue.
Few observers dispute that the most contentious aspect of the U.S. Preventive Services Task Force recommendations related to the age when women should begin routine mammographic screening: 50 versus 40. The key term was “routine,” which was overlooked or ignored, depending on the source, Steven H. Woolf, MD, of Virginia Commonwealth University in Richmond, wrote in one of four commentaries in the Jan. 13 issue of JAMA.
“The USPSTF did not recommend against women having mammograms,” wrote Woolf, a member of or adviser to the task force from 1987 to 2007. “This pivotal misunderstanding resulted from poor wording of the recommendation.”
Specifically, Woolf referred to the following statement: “The USPSTF recommends against routine [emphasis added] screening mammography in women aged 40 to 49 years.”
The sentence was followed by an explanatory statement emphasizing that the decision to begin mammographic screening should be individualized and take into account “the patient’s values regarding specific benefits and harms” (Ann Intern Med 2009; 51: 716-26).
“Inserting ‘routine’ in the first sentence and adding the explanatory second sentence was meant to convey a nuance that was lost on the public,” Woolf wrote. “The panel did not oppose mammography, as widely misinterpreted, but recommended against automatic (‘routine’) imaging, without informing women about potential harms.”
One’s Harm Is Another’s Benefit
Addressing the harm issue in a second commentary, Steven Woloshin, MD, and Lisa M. Schwartz, MD, of Dartmouth Medical School in Hanover, N.H., said that recognizing and understanding the trade-offs of breast cancer screening is a requisite for informed decision making. Most of the discussion about the harms of mammography has focused on false-positive results, which can lead to unnecessary biopsies and associated anxiety and morbidity.
“False-positive test results are not the most important harm of screening — overdiagnosis is,” wrote Woloshin and Schwartz. “Because it is not possible to know which women are overdiagnosed, all are treated with surgery, chemotherapy, radiation, or some combination. Overdiagnosed women are unnecessarily diagnosed, undergo treatment that can only cause harm, and must live with the ongoing fear of cancer recurrence.”
Estimates of the frequency of overdiagnosis range from two to 10 for every cancer death avoided, they added.
Women have divergent views about the benefits and harms of screening. Many women ages 40 to 49 find breast cancer screening worthwhile despite the risk of false-positive results. Others will find the harms too great to accept.
“[That] is exactly the point,” wrote Woloshin and Schwartz. “Each woman, with the help of her physician, needs to consider these harms and benefits and decide whether to undergo screening.”
Seconding a view expressed by Woolf, Woloshin and Schwartz said balanced information is essential for clinical decision making. Noting that the goal of medicine is healthier, longer lives, they wrote “sometimes more testing helps to reach the goal, but other times less testing does. Suggestions to do less may be as much in an individual’s interest as suggestions to do more.”
Anne Murphy, MD, of Johns Hopkins, offered two perspectives on the screening controversy: one from a clinician and researcher and the other from a breast cancer survivor. She implored physicians to address both sides of the issue with their patients.
“Clinicians should specifically discuss the USPSTF recommendations, recognizing that this task force has considered a great deal of medical evidence, but also should discuss that advocacy organizations including the American Cancer Society, the Susan G. Komen for the Cure, and the Avon Foundation for Women still favor the recommendation of yearly mammography screening starting at age 40,” Murphy wrote.
Breast Self-Exam Is Another Issue
Physicians also should be prepared to address women’s questions and concerns regarding another controversial aspect of the USPSTF guideline: The recommendation against the value of teaching women breast self-examination.
“Data from large randomized studies have indicated that this type of formalized breast self-examination may result in more biopsies without reducing the risk of death,” Murphy wrote. “This issue also was addressed in prior clinical practice guidelines and by advocacy organizations, and enthusiasm for teaching formalized breast self-exam has diminished.
“However, a practical issue is that many women present to clinicians and are ultimately diagnosed with breast cancer based on self-palpation of a mass.”
In addressing the benefits of screening mammography, Wendie A. Berg, MD, PhD, also of Johns Hopkins, reviewed four major areas of controversy about the USPSTF recommendations: potential harms, raising the age for routine screening to 50, clinical breast examination, and screening after age 74, which the task force said has no supporting data.
With regard to breast self-examination, Berg said “resources might be better spent on ultrasound in women with dense breasts than on clinical breast examination.” However, she emphasized that women should tell their physicians about any changes detected on self-examination.
Berg referred to “downsides” of mammography, which she said most women would not consider harmful. She cited a survey showing that almost two-thirds of women considered 500 or more false-positive results per life saved would be a reasonable trade-off.
Given that 75% of breast cancers are diagnosed in women with no obvious risk factors, the recommendation against routine screening before age 50 is “problematic,” Berg said in her commentary. She noted progress toward development of other screening modalities to augment mammography for high-risk women. Breast ultrasound and breast MRI have shown promise in selected patients, but both modalities are associated with increased recall rates and more needle biopsies.
Once started, mammographic screening should continue “as long as a woman is in reasonably good health and would pursue treatment if cancer is identified,” Berg wrote. In support of that view, she noted that women in their 80s have an average life expectancy of 8.6 years.
“Annual mammographic screening is appropriate starting at age 40 years, provided the woman is willing to accept the downsides of false positives, including being recalled for more imaging and the possibility of a needle biopsy for a finding that is not breast cancer,” Berg concluded. “The overwhelming majority of women are willing to accept these downsides as part of the process of saving lives otherwise lost to breast cancer.”
Echoing sentiments expressed in the commentaries, an editorial by JAMA editors Catherine D. Deangelis, MD, and Phil B. Fontanarosa, MD, urged physicians and patients to make decisions about screening mammography on the basis of “unbiased, rigorous, objective evaluation of the available evidence for recommendations about screening for breast cancer and other clinical interventions.”
Citing frequent reporting inaccuracies in the news media and the “politicization of biological science,” they also emphasized the need for independent review bodies, such as the USPSTF, to offer “objective appraisals, reports, and guidelines without concern about special interests, politics, or ideology or fear of repercussions for seeking the truth in providing evidence-based recommendations.”
“In issuing the 2009 recommendation statement, the USPSTF has fulfilled its mandate to provide guidance and evidence that will help physicians and patients make informed, individualized decisions about screening for breast cancer” they wrote.
Woolf, Woloshin, Schwartz, DeAngelis, and Fontanarosa reported no disclosures. Berg disclosed relationships with Naviscan and Medipattern. Murphy disclosed relationships with the American Cancer Society, Susan G. Komen for the Cure, Avon Foundation for Women, and the Lance Armstrong Foundation.