Diagnostic accuracy of lightscanning and mammography in women with dense breasts.

The diagnostic accuracy of lightscanning and mammography in 610 breasts with mammographically dense parenchymal patterns was investigated. Lightscanning identified 31 out of 36 cancers and mammography 32. Lightscanning and mammography were in agreement in 28 cases of cancer. One noninvasive lobular carcinoma was not identified by either modality. Four cancers were not correctly identified with lightscanning alone and 3 cancers with mammography alone. Of the 574 breasts without cancer, lightscanning falsely denoted 101 (18%) as possibly being cancerous (false-positives). The corresponding figure for mammography was 25 (4%). Thus, lightscanning, as performed in this study, has the same sensitivity as mammography in detecting cancer in mammographically dense breasts. However, its usefulness is limited by a low predictive value of a positive test (high rate of false-positives).