Follow-Up for Women with Abnormal Mammograms

The American Cancer Society's guidelines for early detection of breast cancer recommend yearly mammograms for all women beginning at age 40.1 Considerable controversy arose when the U.S. Preventive Services Task Force (USPSTF) revised its mammography screening guidelines in 2009 to include recommendations against routine screening of women aged 40 to 49 (with the decision to screen women younger than 50 to be made based on individual risk factors) and in favor of biennial screening in women aged 50 to 74 (JW Womens Health Nov 16 2009). Mammographic sensitivity ranges from 83% to 95%, and specificity ranges from 93% to 99%.2 Furthermore, sensitivity and specificity are lower in women who are younger than 50. Thus, 5% to 10% of all screening mammograms are reported as abnormal, and — more importantly — about 90% of women with abnormal mammograms do not have breast cancer.3 Appropriate and timely follow-up of abnormal mammograms is crucial for relieving patients' anxiety and for assuring prompt intervention if malignancy is present. Optimal strategies for managing patients with abnormal mammograms should allow clinicians to rapidly identify those patients who have breast cancer, and, with the same speed and accuracy, to identify (and reassure) those who do not.

Preliminary Assessment

All women should undergo clinical breast examination at some point prior to mammography so that clinicians can ascertain any palpable abnormalities or clinical evidence of breast cancer, such as Paget disease (which appears as an erythematous change in the skin of the nipple-areolar complex that might not be associated with any radiologic abnormality). Preliminary clinical examination raises the sensitivity of mammography substantially.4

Interpreting “Abnormal”

Defining the term “abnormal mammogram” (and knowing the implications of that definition) is essential. The American College of Radiology has developed the Breast Imaging Reporting and Data System (BI-RADS; see table), in which six categories for reporting complete mammographic findings are delineated.5

Women whose mammographic results fall into BI-RADS categories 1 and 2 do not require further imaging and safely can be screened again in 1 or 2 years. A categorization of 3 is associated with low potential for breast cancer (positive predictive value for malignancy, 0% to <2%).6 The most common strategy for this patient group is either to repeat the imaging in 6 months or to perform ultrasound-guided biopsy for concordance. If the lesion has progressed after 6 months, biopsy is mandatory; if the lesion has remained stable, repeat imaging in another 6 months is recommended. An opinion from a breast cancer surgeon usually is not required for BI-RADS category 3. Recently, the BI-RADS category 4 definition was stratified into 3 subcategories: BI-RADS 4A, 4B, and 4C are associated with positive predictive values for malignancy of 13%, 36%, and 79%, respectively.6 BI-RADS categorizations of 4 or 5 mandate urgent pathologic evaluation with biopsy. A BI-RADS categorization of 0 implies that more imaging is needed; risk for breast cancer ranges from 2% to 10% in this population.4 Additional imaging with diagnostic mammography or ultrasonography usually is performed and, if discordance persists, pathologic assessment with biopsy is mandatory.

Biopsy Choices

Several tissue-sampling techniques are available. Appropriate methods for nonpalpable lesions include image-guided fine-needle aspiration (FNA), core-needle or vacuum-assisted biopsy, and stereotactic or needle-localized open surgical biopsy. Image-guided FNA and core-needle biopsies are faster, easier, and less expensive, and are associated with lower morbidity than are stereotactic or needle-localized open biopsies. Core-needle biopsy, with its sensitivity of at least 93% and specificity of at least 95%, is preferred over FNA.4 In addition, this technique yields more tissue for histologic evaluation and, therefore, can more accurately profile tumors preoperatively than can FNA.7 FNA should only be used for lesions close to the chest wall or to the overlying skin, where core-needle biopsies are difficult and potentially dangerous.

Further Evaluation

The most common mammographic abnormalities appear as masses or calcifications. Differential diagnoses are numerous and range from completely benign to noninvasive and invasive carcinomas of the breast. Abnormal mammograms require further evaluation with additional diagnostic mammographic imaging or ultrasonography. Diagnostic mammographic imaging is used to evaluate lesions more closely and usually consists of specialized views (e.g., magnification or spot compression views). If this is inadequate, then a biopsy or further imaging with ultrasound might be beneficial. Ultrasonography can determine more accurately whether a mass is solid or cystic and can be used to guide biopsies. Routine use of magnetic resonance imaging in the setting of abnormal mammography is not recommended, as this imaging mode often identifies other equivocal lesions in either breast, leading to additional biopsies without further patient benefit.8

Promoting Adherence to Follow-Up

According to the National Cancer Institute, 9% of women with abnormal mammograms are nonadherent regarding additional follow-up. Factors associated with excess risk for nonadherence to follow-up include age younger than 50, poor health, and less than high school education. In contrast, patients with family histories of breast cancer are more likely to adhere to follow-up recommendations.9 From clinicians' perspectives, documentation and communication play crucial roles in follow-up for patients with abnormal mammograms. Precisely detailing the management plan in the medical records and ensuring that patients understand the importance of follow-up are necessary for effective care.10 All clinicians should practice appropriate follow-up of all patients with abnormal findings — but especially results of cancer screening tests — and should refer patients to relevant specialists. Given that 10% of patients with abnormal mammograms have breast cancer, accurately identifying these patients in a timely fashion is critical to ensure that they receive optimal cancer care.