Abstract P6-02-04: Ultrasound assessment of residual disease after neoadjuvant chemotherapy (NACT) in node positive triple negative breast cancer (TNBC)

Abstract

Abstract Purpose: To determine accuracy of preoperative ultrasound after NACT to predict residual disease in triple negative breast cancer (TNBC) patients with confirmed axillary nodal metastasis. Methods: This is an institutional review board approved retrospective study of TNBC patients who received NACT at MD Anderson Cancer Center from January 1999 - June 2015. We identified 327 TNBC patients who had cytologically confirmed breast and nodal disease at baseline evaluation and had preoperative ultrasound evaluation of residual disease. Ultrasound response was divided in tree categories: radiologic complete response (rCR) - complete resolution of the malignant mass); near-rCR - no discernible mass, only an isoechoic flat tumoral bed); and residual disease (RD) - a discernible mass is seen. Axillary ultrasound images were evaluated for lymph node size, cortical thickness and residual morphological type after NAC (type I-VI). Ultrasound breast and axillary findings were compared with final surgical pathology. Results: In 89 cases (27%), pCR was achieved. 74% (242/327) were unifocal and 26% (86/327) multifocal. Ultrasound rCR was seen in 11% patients (36/327). Of those, 64% (23/36) showed pCR and 36% (13/36) showed residual disease. Ultrasound near-rCR was seen in 26% (84/327). Of those, pCR was seen 49 % (41/84) and residual disease in 51% (43/84). Residual disease was seen in 63% (207/327), 12% (25/207) showed pCR and 88% (182/207) showed residual disease. Regarding axillary lymph nodes, long axis diameter mean was 1.57 cm for patients with pCR and 1.6 cm for no pCR, short axis diameter mean was 0.67 cm for pCR and 0.87 cm for no pCR. Cortical thickness mean was 2 mm for pCR versus 9 mm for no pCR. Sensitivity of ultrasound for assessment residual disease (ultrasound was considered positive if either breast ultrasound or axillary ultrasound showed residual disease) was 97%. Specificity is 22.47% with a NPV of 74% and PPV of 77%. Conclusion: Breast and axillary ultrasound performed after NACT showed low specificity but high sensitive to detect residual disease. rCR and near rCR were related with pCR in 64% and 49 % of the cases respectively. Citation Format: Adrada BE, Valero V, Reddy SM, Barcenas CH, Candelaria R, Wei W, Rauch GM. Ultrasound assessment of residual disease after neoadjuvant chemotherapy (NACT) in node positive triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-02-04.