Abstract P6-02-10: Early ultrasound evaluation for prediction of treatment response to neoadjuvant chemotherapy in triple negative breast cancer patients

Background: Triple negative breast cancer (TNBC) is molecularly heterogeneous disease. Genomic profiling to identify the distinct TNBC subtypes is costly with long turnaround time. Early ultrasound after two cycles of neoadjuvant chemotherapy (NAC) has the potential to identify patients who are likely to have pathological complete response. Suspected non-responder patients can undergo comprehensive genetic testing and triaged for specific targeted therapeutic trials. Aim: To determine the value of ultrasound evaluation after two cycles of NAC to predict complete pathologic response in TNBC breast cancer patients. Methods: 98 patients enrolled in “A randomized triple Negative Breast Cancer Enrolling Trial to Confirm Molecular Profiling Improves Survival” (Artemis) at the University of Texas MD Anderson Cancer Center had ultrasound evaluation before treatment and after two cycles of NAC (Adriamycin and Cyclophosphamide). Three-dimensional measurements of the tumor were obtained at baseline and after 2 cycles of the NAC. Change in the tumor volume after 2 cycles of NAC was calculated. Residual cancer Volume (RCB) was calculated based on the final histopathology at surgery. Linear regression analysis evaluated associations between residual cancer burden (RCB) and change in volume of the index tumor. Results: Median tumor size at diagnosis was 3 cm, range 0.6-11.9cm. Median size after two cycles was 2 cm, range 0.6-12.8 cm. RCB 0-I was seen in 55% of patients (54/98). Linear regression analysis demonstrated that of 22 patients with volume reduction >75%, 18 patients (82%) had RCB0-I (95%CI, 61%-93%). Conclusion: Our data suggest that ultrasound exam after 2 cycles of NAC can identify TNBC patients who are unlikely to respond to standard NAC. These non-responder TNBC patients can be triaged for additional genetic testing and subsequent targeted clinical trials. Study on the larger number of patients is currently on the way. Citation Format: Adrada BE, Candelaria R, Moulder S, Lane D, Santiago L, Arribas E, Hess KR, Valero V, Thompson A, Helgason T, Ravenberg E, Yang W, Rauch GM. Early ultrasound evaluation for prediction of treatment response to neoadjuvant chemotherapy in triple negative breast cancer patients [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 P6-02-10.