Accuracy of MRI, mammography (MG), and 2D and 3D ultrasound (2DUS/3DUS) in determining the pathologic tumor response after neoadjuvant chemotherapy (NACT) in breast cancer patients.

Abstract

1067 Background: The pathological tumor response in patients with locally advanced breast cancer to NACT is essential for survival and for surgical strategies. Therapy monitoring based on German recommendations is routinely performed by clinical examination, MG and 2DUS. The clinical value of MRI and 3DUS has not been established yet. The aim of the study was to determine the accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) between the different imaging techniques in predicting postoperative histological tumor response after NACT. Methods: Patients with primary breast cancer (cT1-T4, cN0-1, M0) undergoing neoadjuvant chemotherapy between 2005 and 2010 were eligible for this prospective trial. The response was measured by MRI, MG, 2DUS and 3DUS for complete or partial remission versus stable disease after the last cycle of treatment and compared with the final pathological response. Patients with progressive disease were excluded from the study. Statistical analysis was done by calculating the accuracy of each imaging technique and the size difference between imaging and histological tumor size. Sensitivity, specificity, PPV and NPV were calculated for complete or partial pathological response. The study was approved by the local ethic committee (BCD001 194/2004). Results: 103 patients with the mean age of 47.7 (range 24.5 – 71.4) years were evaluated. The accuracy was 0.680 (95%CI: 0.580 -0.768) for MRI, 0.563 (95%CI: 0.453-0.669) for MG, 0.724 (95%CI: 0.618 -0.815) for 2DUS and 0.710 (95%CI: 0.588-0.813) for 3DUS. Sensitivity, specificity, PPV and NPV were 78%, 47%, 75% and 52% for MRI, 61%, 45%, 69% and 36% for MG, 93%, 23%, 74% and 60% for 2DUS, 94%, 19%, 73% and 57% for 3DUS. The mean (standard deviation) size difference was -1.8 mm (14.8) on MRI, 1.5 mm (26.0) on MG, -9.1mm (19.1) on 2DUS and for the volume difference -6916mm3 (15831) on 3DUS. Conclusions: The data suggest that 2DUS is sufficient in predicting tumor response between NACT treatment. MRI and MG are more accurate the 2DUS in predicting the tumor size for surgical planning.