Objective: The purpose of this study was to evaluate the applicability of the current BI-RADS for sonography to the assessment of synchronous breast nodules other than the primary malignant tumor in patients with breast cancer.
Materials and methods: One hundred eighty-nine synchronous nodules in 147 breast cancer patients were surgically excised after localization, and 412 synchronous nodules in 191 patients were observed or biopsied or excised without localization. Among a total of 601 synchronous nodules, 372 nodules were ipsilateral and 229 were contralateral to a primary malignant tumor. Two radiologists retrospectively reviewed sonograms of these nodules and determined the sonographic BI-RADS category without clinical information or pathologic results. For each nodule, the preoperative BI-RADS category and pathologic or follow-up results were compared.
Results: Four hundred eighty-two nodules were classified category 3; 112 nodules, category 4; and seven nodules, category 5. Fifty-five (11.4%) of the category 3 nodules and 57 (47.9%) of the category 4 and 5 nodules were confirmed malignant. Thirty-six (21.2%) of 170 category 3 synchronous nodules in the same quadrant as the primary tumor were confirmed malignant, as were 12 (9.8%) of 122 nodules in a different quadrant and eight (4.2%) of 190 nodules in the contralateral breast.
Conclusion: For assessment of synchronous nodules in breast cancer patients, application of conventional screening sonographic BI-RADS categories may not account for possible increased risk of malignancy in synchronous nodules, especially those in the same quadrant of the breast as the index malignant tumor.