Change in sonographic brightness can predict pathological response of triple-negative breast cancer to neoadjuvant chemotherapy

Ultrasound (US) is conventionally performed to determine effects of neoadjuvant chemotherapy (NAC) on breast cancer. In patients with triple-negative breast cancer (TNBC), higher pathological complete response (pCR) predicts the most favorable survival outcome. We aimed to predict pCR to NAC using echogenicity changes in US region of interest (ROI) in patients with TNBC. We retrospectively determined clinicopathological characteristics of 52 patients with primary TNBC who underwent NAC. Changes in echogenicity for pCR and non-pCR patients were calculated from ratios of tumor to fat (T/F) in their ROIs, before and after NAC, as [T/F (After)/T/F (Before)] and [T/F (After) - T/F (Before)]. Of the 52 patients (median age: 52 years; range 26-77 years), 20 (38.5%) achieved pCR, which was significantly associated with change in ROI ratio (P < 0.01). The cut-off values for ROI ratio and ROI difference were 0.8 and 0.3. Sensitivity and specificity were 73.7 and 81.8% for ROI ratio, and 70.0 and 81.3% for ROI difference. Area under the curves (AUCs) for ROI ratio and ROI difference were 0.80 [95% confidence interval (CI) 0.67-0.92] and 0.78 (95% CI 0.64-0.92), respectively. Quantification of echogenic changes by converting absolute values of tumor and fat regions can predict pCR and individual differences between tumors after NAC in patients with TNBC.