Multiple bilateral masses detected on screening mammography: assessment of need for recall imaging

When multiple bilateral partially circumscribed masses having a similar appearance are detected on screening mammography, some radiologists recommend recall examination to identify imaging features suggestive of malignancy that are not evident on standard screening views. This study assesses the need for such recall imaging.

Cases of multiple masses were identified by reviewing the mammographic reports of 84,615 consecutive screening examinations. Each case of multiple masses was prospectively interpreted as benign, with recommendations for follow-up mammography in 1 year and for aspiration of any palpable masses if clinically indicated. Subsequently diagnosed cancers were identified through data linkage with our regional tumor registry and through our institution's computer-based outcomes tracking system.

Among 84,615 consecutive screening examinations, we identified 1440 (1.7%) cases of multiple masses. Among the multiple-masses cohort, two interval cancers were found. Both were early-stage (T1bN0M0; T1cN0M0) and low-grade (histologic grade 1) cancers. The interval cancer rate among the multiple-masses cohort was 0.14%, which is somewhat lower than the age-matched United States incident cancer rate of 0.24%.

The frequency of cancer development and the stage at cancer diagnosis among nonrecalled cases of multiple masses are similar to those observed in the general screening mammography population. Therefore, recall imaging for women with multiple masses does not appear to be justified.