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Breast Imaging

E2424. Value of Targeted Ultrasound in Evaluating Palpable Breast Findings: A Study Based on Breast Density

Zheng K,  Komarla R,  Rodriguez K,  Ho C,  Newell M. Emory University, Atlanta, GA

Address correspondence to K. Zheng (kszheng@emory.edu)

Objective: The standard of care for the evaluation of a palpable breast abnormality in patients 30 years or older is combined mammography and ultrasound, which has been shown to have a near 100% negative predictive value (NPV) for the detection of malignancy. In the setting of lower breast density, however, ultrasound may not add diagnostic value if mammography findings are negative for suspicious lesions. The purpose of this study is to determine the NPV of mammography alone for evaluating a palpable abnormality in each breast density category.

Materials and Methods: After institutional review board approval, our institutional data warehouse was queried (January 1, 2012–January 1, 2014) for diagnostic mammogram and ultrasound studies performed on patients age 30 years and older presenting with a palpable breast abnormality. Search terms were “palpable,” “mass,” “thickening,” and “lump.” The NPV of mammography alone for detecting malignancy was calculated in each breast density group. Patients who were lost to follow-up after a recommendation for biopsy were excluded from NPV calculations. The cases in which a suspicious finding was seen on ultrasound after a negative mammogram were recorded, as were the biopsy pathology results. Patient demographics, personal and family history of breast cancer, years of follow-up, and incidental suspicious findings prompting biopsy were also recorded.

Results: The study included 609 palpable abnormalities in 553 patients (mean age, 50 years). Of these patients, 12% had a personal history of breast cancer and 41% had a family history of breast cancer. The NPV of mammography alone was 98.5%, with breakdown by breast density category as follows: 100% almost entirely fat, 97.4% scattered fibroglandular, 98.3% heterogeneously dense, and 100% extremely dense. Nineteen percent (118/609) of all palpable abnormalities had ultrasound findings that were not seen on mammography. Fifty-two percent (61/118) of these findings prompted biopsy; 5% (6/118) were malignant, and less than 1% (1/118) were high risk. In the almost entirely fatty and extremely dense groups, none of the palpable abnormalities seen by ultrasound alone were malignant. There were 59% of palpable abnormalities that did not receive a diagnosis of malignancy and were in an age group for continued screening mammography that had at least 1 year of follow-up; no interval cancers were found. There were 30 incidental suspicious findings elsewhere in the breasts (not at the site of palpable concern) requiring biopsy. One (2%) was malignant and was seen on both mammography and ultrasound. Two (7%) were lost to follow-up.

Conclusion: The NPV of mammography alone for the detection of malignancy (99%) is comparable to combined ultrasound and mammography (near 100%), with a 100% NPV in the almost entirely fatty breast density group. Although ultrasound yielded a higher than expected number of findings not seen on mammography, only 5% were malignant, none of which were in the almost entirely fatty group. Our findings suggest that palpable abnormalities in this group of patients can be safely evaluated by mammography alone, which would be both cost- and time-effective without compromising the quality of care.