Negative Predictive Value of Ultrasound in Predicting Tumor-Free Margins in Specimen Sonography

To evaluate the success of ultrasound in post-excision specimen visualization, and negative predictive value of ultrasound for estimation of tumor-free margins using histopathology as the gold standard.

Cross-sectional analytical study.

The Aga Khan University Hospital, Karachi, Pakistan, from May 2010 till January 2013.

Sonography of all breast nodules was done before and after exicision by two female radiologists with at least five years clinical experience. All surgeries were performed by the same referring breast surgeons. All nodules were non-palpable and had histopathology as well as specimen sonography performed at AKUH. Subjects were excluded, if histopathology was not available, post-procedure sonogram not done or done in another hospital and nodules that were not seen on ultrasound. After needle localization in 47 patients using ultrasound and in 7 patients using mammogram was done, sonogram was conducted in all 54 lesions. These were then assessed by ultrasound for detection of lesion and tumor-free margins in malignant lesion. Post-excision ultrasound was performed for the evaluation of lesion whether visualized or absent with localizing needle in situ, lesion dimensions, depth measurement between the superior margin of the lesion and its edge.

All 54 lesions were present on post-exicison scan, out of which 28 were documented as malignant and 26 as benign. Ultrasound declared all specimens as tumor-free. On histopathology, two lesions were documented as having tumor-positive margins and were proven to be invasive lobular carcinoma. Therefore, the negative predictive value of the specimen sonography for margin detection was 26/28 (92.8%).

Ultrasound of the excised breast tumor specimen is a simple and reliable technique for confirmation of the tumor-free margins in non-palpable breast lesions.