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Practice GUIDELINES

Breast Cancer Screening Updates

Dana M. Chase, MD; Krishnansu S. Tewari, MD

The new USPSTF breast cancer screening guidelines and the wide media attention they have received have created confusion and concern among both patients and clinicians. Here are 7 common screening scenarios that highlight specific clinical situations and offer reasonable ways to address them.

Breast cancer is unavoidable in any medical practice involving health care for women. It was responsible for an estimated 192,370 cases and 40,170 deaths in the US in 2009.1 Many patients have questions and concerns regarding breast cancer screening, especially since the new recommendations were published from the US Preventive Services Task Force (USPSTF) (Table).2 As with cervical cancer screening, the ideal protocol would reduce unnecessary and perhaps invasive procedures while maintaining or decreasing rates of breast cancer. This article will review these recent recommendations through the presentation of common cases that address 5 methods of screening: film mammography, digital mammography, breast magnetic resonance imaging (MRI), self breast examination (SBE), and clinical breast examination (CBE) (Figure 1).

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TABLE. TABLE. Summary of USPSTF Recommendations for Breast Cancer Screening.2

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FIGURE 1. Sensitivity and specificity of 5 breast cancer screening modalities.2

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Case #1: First Mammogram

A 40-year-old woman presents to your office asking for her first mammogram. Based on the recent USPSTF recommendations, what do you advise her?

The 2009 recommendations from the USPSTF indicate that annual breast cancer screening between ages 40 and 49 is no longer advised. The benefit of screening mammography is in its ability to reduce breast cancer mortality. However, the ability to reduce breast cancer mortality is strongest among women older than 49. The USPSTF guidelines list the risks of early screening: psychological harm, unnecessary imaging and biopsies, inconvenience, unclear evidence that early detection lengthens life in certain cases, detection of early cases that will never cause danger in a woman’s remaining life span, and radiation exposure. The main issue highlighted is the large number of false-positives in younger women and the diagnosis of multiple cases in older women where perhaps earlier diagnosis will not impact overall life span.

Several commentaries were published in JAMA shortly after the new USPSTF guidelines appeared. One commentary describes how without screening, 3.5 of 1,000 women in their 40s will die of breast cancer over the next 10 years, whereas screening with mammography only reduces the risk to 3.0 of 1,000.3 In response, ACOG issued an official statement that acknowledges the controversy and latest data behind the newest recommendations for screening but continues to recommend screening mammograms every 1 to 2 years in women ages 40 to 49.4 ACOG does note, however, that these age-groups may suffer the harm of mammography more so than their older counterparts.

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Case #2: Clinical Breast Examination

A 45-year-old woman presents to your office for her annual exam. She would like to know if she needs to undress completely for a breast exam. What do you advise her?

Overall, CBEs add little to routine screening with mammography. Perhaps many clinicians are also not routinely practicing this technique. Unfortunately, there is no current standard approach or a standard means to report the findings.2 Some theorize that CBE may detect a significant proportion of cases if it is the only screening test available. In a Cochrane review published in 2003, the authors do not draw a conclusion regarding CBE secondary to lack of evidence and/or well-designed studies.5 Thus, while perhaps convenient in terms of an addition to the standard well-woman exam, the question becomes, again, whether CBE leads to more invasive tests and unfounded patient anxiety. Some suggest that with biennial mammograms, the best way to reduce breast cancer mortality is to continue CBE annually. This is more cost-effective than both procedures being performed annually, and the effect of biennial mammograms is thought to possibly be supplemented by annual CBE.

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Case #3: Teaching Self Breast Examination

A 21-year-old presents for her first Papanicolaou test. Her mother has instructed her on SBE. She would like you to describe the proper way to conduct this exam. What do you tell her?

The new USPSTF recommendations suggest that the harms of SBE outweigh the benefits. In 2008, a Cochrane review was updated, examining the efficacy of SBE.5 The researchers reported 2 large studies comparing SBE to no intervention in the prevention of breast cancer. Unfortunately in these studies, one in Shanghai and one in Russia, the benefit of SBE either did not exist or was very small. Furthermore, they reported twice as many biopsies for false-positive SBE in the intervention groups. This review emphasizes the resulting emotional distress and invasive procedures resulting in scars and deformities stemming from the recommendations to perform SBE. Despite these data, the authors stressed that looking for and detecting changes in a woman’s breast may be important to emphasize with patients, without a formal recommendation for routine self-exams. Because of this review and supporting evidence, some major societies have discontinued their emphasis on SBE (Figure 2).

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FIGURE 2. Recommendations of major societies for mammography, self breast examination (SBE), and clinical breast examination (CBE).

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Case #4: After Menopause

A 60-year-old woman presents to your office for her examination. She has been receiving mammograms annually and wants to know how these new screening guidelines affect her. Do you screen her annually?

The new guidelines recommend breast cancer screening biennially for women ages 50 to 74. It has been well documented that women in their 60s benefit the most from screening.2 For this age-group, the benefit of screening is at least moderate compared to their younger counterparts. In those ages 50 to 59, the systematic review highlighted above describes the need to screen 1,339 women to avoid a single breast cancer mortality, which is further decreased to 377 screened women in the next decade of life (ages 60 to 69). Changing from annual to biennial screening reduces the harm of mammography by nearly half. These new recommendations suggest that a detailed discussion between patient and clinician must occur to outline the individual risk-benefit preferences before extending the mammogram biennially. Again, ACOG has not yet accepted these new biennial guidelines and reports to their fellows that they will need to evaluate these changes in greater depth before accepting them into their own recommendations.

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Case #5: Elderly Women

An 80-year-old woman presents to your office for her annual exam. Her internist told her that she must continue to receive mammograms. She asks for your opinion on this matter. What do you tell her?

The USPSTF concluded that the evidence is insufficient to recommend breast cancer screening in women older than 74. The new guidelines suggest 3 reasons for these changes:

• The questionable effect of detecting breast cancer in a group of women who have a lower survival rate to begin with
• The higher percentage of good prognostic (estrogen receptor–positive) cases in this age-group
• Women in this age-group are at much greater risk of dying from other conditions.

The USPSTF introduces the concept of overdiagnosis here to describe diagnosing a cancer that will never actually become clinically “important,” because the woman would likely die before the cancer becomes deadly. The uncertainty of morbidity and perhaps imminent mortality in this group presents a challenge for creating cancer screening recommendations. With a higher incidence of cancer in this population and a higher 5-year all-cause mortality rate, counseling should probably be individualized. Perhaps aggressive cancer screening in this population may lead to increased morbidity from treatment in patients with limited life span.

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Case #6: Specialized Imaging

A 65-year-old woman taking hormone replacement therapy reports she has fibrocystic breasts and, despite negative mammograms, would like to know if she should get a more specialized breast exam, such as a breast MRI or digital mammography. What do you advise her?

Overall, the USPSTF found the evidence lacking to support either breast MRI or digital mammography. Both exams are costly and more expensive than a mammogram. Although there is speculation that they have improved diagnostic ability to detect cancers in younger women with dense breast tissue, there is an unclear overall effect on mortality in these women. Although mammography has been shown to be an effective screening tool that lowers the mortality rates in women with breast cancer, it does have limitations, especially in women with dense breasts. New imaging tools not only overcome the limitations of mammography but also potentially detect the disease earlier. One of these new techniques is MRI of the breast. Two important roles for breast MRI is in screening patients with very dense breasts as well as those women at particularly high genetic risk for breast cancer. In recent years, the resolution of breast MRI has improved to such a level that it is even possible to detect small breast cancers while they are still in the noninvasive state, ie, before they develop the ability to spread. Breast MRI may also be useful in determining the extent of disease in patients diagnosed with breast cancer, before they start treatment.

There is some good evidence, however, that supports use of MRI in screening.6,7 Furthermore, the American Cancer Society (ACS) guidelines recommend MRI be used in addition to mammography to screen high-risk women.8 Disadvantages of breast MRI include a high false-positive rate that may result in unnecessary repeat testing and biopsies.

Digital mammography is another recent screening tool. With this technique, the image is captured electronically and stored. In a review article, the benefits of digital mammography are outlined as improved diagnostic accuracy, especially in cases of dense tissue; easier archival, retrieval, and transmission of images; the use of computer-aided detection; and the potential for telemammography and teleconsultation.9 The largest trials have failed to demonstrate an advantage in the use of this technique, however. Therefore, the USPSTF does not recommend this imaging technique for the general public.

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A 41-year-old woman presents to your office for her well-woman exam. She states that recently her sister was diagnosed with breast cancer and tested positive for the BRCA1 genetic mutation. She wonders whether she is eligible for routine screening with the new guidelines.

Patients with known BRCA1 or BRCA2 genetic mutations have about 4 to 5 times the lifetime risk of the general population to be diagnosed with breast cancer. In these women, the latest recommendations do not apply. (They also do not apply to those who have received chest radiation.) The National Comprehensive Cancer Network (NCCN) and the ACS instead recommend that monthly SBE begin at age 18, that CBE be performed 2 to 4 times per year beginning at age 25, and annual mammography and breast MRI begin at age 25 or earlier depending on the earliest age of breast cancer in the family.8 The patient with a strong family history (ie, unknown mutation status) should be referred for genetic counseling and/or testing.

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SUMMARY

As annual mammography has largely become an accepted practice in women older than 40, the updated guidelines present a drastic shift in screening dogma. The mammogram is a well-respected and well-used modality and is endorsed strongly by many experts and associations. The latest USPSTF guidelines place many physicians in a difficult clinical decision-making situation. To shift counseling away from screening may cause anxiety in both the patient and clinician, especially when the widespread acceptance from the general public is that breast cancer mortality has largely declined as a result of strict adherence to mammography. However, new data from randomized trials are difficult to ignore, so this dogma must be challenged. Despite the proof against frequent screening and the concern for harm to patients greater than benefit, the USPSTF still recommends individualizing counseling and screening protocols with patients. It is perhaps because of the reluctance to place stronger emphasis on reducing screening that ACOG has not yet accepted these challenges. Hopefully, this review has shed some light on this debate. The media's campaign to sensationalize these changes has been problematic, as it has instilled doubt in our patients regarding our screening recommendations.

The authors report no actual or potential conflicts of interest in relation to this article.

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Dana M. Chase, MD, is Clinical Instructor, and Krishnansu S. Tewari, MD, is Associate Professor, both at the Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Chao Family Comprehensive Cancer Center, University of California, Irvine Medical Center, Orange, CA.

References

1. American Cancer Society. Cancer Facts & Figures 2009. Atlanta, GA: American Cancer Society; 2009.
2. US Preventive Services Task Force. Screening for breast cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2009;151(10):716-726.
3. Woloshin S, Schwartz LM. The benefits and harms of mammography screening: understanding the trade-offs. JAMA. 2010;303(2):164-165.
4. ACOG. Response of the American College of Obstetricians and Gynecologists to New Breast Cancer Screening Recommendations from the U.S. Preventive Services Task Force. November 16, 2009. www.acog.org/from_home/Misc/uspstfresponse.cfm. Accessed March 8, 2010.
5. Kösters JP, Gøtzsche PC. Regular self-examination or clinical examination for early detection of breast cancer. Cochrane Database Syst Rev. 2003;(2):CD003373.
6. Kuhl CK, Schrading S, Bieling HB, et al. MRI for diagnosis of pure ductal carcinoma in situ: a prospective observational study. Lancet. 2007;370(9586):485-492.
7. Lehman CD, Gatsonis C, Kuhl CK, et al. MRI evaluation of the contralateral breast in women with recently diagnosed breast cancer. N Engl J Med. 2007;356(13):1295- 1303.
8. Saslow D, Boetes C, Burke W, et al. American Cancer Society guidelines for breast screening with MRI as an adjunct to mammography. CA Cancer J Clin. 2007;57(2):75-89.
9. Skaane P. Studies comparing screen-film mammography and full-field digital mammography in breast cancer screening: updated review. Acta Radiol. 2009;50(1):3-14.

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