Positive predictive value of additional synchronous breast lesions in whole-breast ultrasonography at the diagnosis of breast cancer: clinical and imaging factors

PURPOSE: To evaluate the positive predictive value (PPV) of bilateral whole-breast ultrasonography (BWBU) for detection of synchronous breast lesions on initial diagnosis of breast cancer and evaluate factors affecting the PPV of BWBU according to varying clinicoimaging factors. METHODS: A total of 75 patients who had synchronous lesions with pathologic confirmation at the initial diagnosis of breast cancer during January 2007 and December 2007 were included. The clinical factors of the patients were evaluated. One observer retrospectively reviewed the imaging studies of the index breast cancer lesion and the synchronous lesion. The PPV for additional biopsy was calculated for BWBU and various clinical and imaging factors affecting the PPV for BWBU were evaluated. RESULTS: The overall PPV for additional biopsy was 25.7% (18 of 70). The PPV for synchronous lesions detected both on mammography and BWBU, and detected only on BWBU, was 76.9% (10 of 13) and 14.3% (7 of 49), respectively. There was no clinical factor affecting the PPV for BWBU. Among the imaging factors, ipsilateral location of the synchronous lesion to the index lesion (P=0.06) showed a marginal statistically significant correlation with malignancy in the synchronous breast lesion. A mass with calcification on mammography presentation (P<0.01), presence of calcification among the ultrasonography findings (P<0.01), and high Breast Imaging Reporting and Data System final assessment (P<0.01) were imaging factors that were associated with malignancy in the additional synchronous lesion. CONCLUSION: BWBU can detect additional synchronous malignancy at the diagnosis of breast cancer with a relatively high PPV, especially when mammography findings are correlated with ultrasonographic findings.