Background: The presence of tumor-infiltrating lymphocytes (TILs) is a prognostic factor for breast cancer. However, because of tumor tissue heterogeneity, an accurate and simple evaluation method is needed. We determined if preoperative characteristic ultrasonography (US) image findings are predictive of lymphocyte-predominant breast cancer (LPBC).
Methods: We evaluated 191 patients with invasive breast cancer treated by curative surgery between January 2014 and December 2017. Stromal lymphocytes in surgical pathological specimens were evaluated. Fifty-two patients with ≥ 50% stromal TILs were defined as having LPBC. Preoperative US images were examined for indicators of TILs. The US images with characteristic TILs were scored for prediction of LPBC.
Results: Shape (more lobulated), internal echo level (weaker), and posterior echoes (stronger) were predictors of LPBC and used to assign the TILs-US scores (0-7 points); the score cutoff for predicting LPBC was 4 points (sensitivity, 0.73; specificity, 0.87; accuracy, 0.83) based on the receiver operating characteristics (ROC) curves (AUC 0.88). Multivariate logistic regression analysis identified nuclear grade (NG), OR 3.4; estrogen receptor (ER), OR 5.7; human epidermal growth factor receptor type-2 (HER2), OR 4.1; and TILs-US score, OR 14.9 as LPBC predictors (all, p < 0.05). The sensitivity, specificity, and accuracy for predicting LPBC were 0.75, 0.69, and 0.71 for NG and 0.33, 0.96, and 0.79 for ER and HER2, respectively. ROC analysis showed that the diagnostic abilities of NG, ER, and HER2 were lower than that of the TILs-US score.
Conclusions: LPBC showed characteristic US imaging findings. The TILs-US score was an accurate preoperative predictor of LPBC.
Keywords: Breast cancer; Lymphocyte-predominant breast cancer; Tumor-infiltrating lymphocytes; Ultrasonography.