Predictive significance of breast-specific gamma imaging for upstaging core-needle biopsy-detected ductal carcinoma in situ to invasive cancer

Objective: We evaluated the significance of breast-specific gamma imaging (BSGI) for determination of upstaging to invasive cancer from preoperative ductal carcinoma in situ (DCIS). Methods: This study enrolled 168 patients with 175 breast lesions diagnosed as DCIS on core-needle biopsy that subsequently underwent preoperative BSGI between September 2011 and October 2017. Both qualitative and quantitative analyses using tumor-to-normal background ratio (TNR) and coefficient of variation (COV) were performed, and the predictive significance for upstaging to invasive cancer was investigated. We also sought to identify clinicopathological factors associated with upstaging and their relation to BSGI findings. Results: Fifty-eight lesions (33.1%) were confirmed to be invasive breast cancer after the final surgical approach. On univariate analysis, tumor size based on ultrasonography (US), hormone status, histologic grade, Breast Imaging Reporting and Data System category, comedo-necrosis, Ki-67 expression, and BSGI findings were associated with upstaging to invasive cancer. Tumor size > 2.0 cm (p = 0.005), Ki-67 expression > 8% (p < 0.001), qualitative BSGI findings (p = 0.020), and COV > 30.44 (p = 0.022) were independently associated with upstaging after multiple regression analysis. Conclusion: BSGI is a useful imaging modality for predicting upstaging to invasive breast cancer from DCIS on core-needle biopsy in conjunction with US tumor size and Ki-67 expression.