MRI volume measurements compared with the RECIST 1.1 for evaluating the response to neoadjuvant chemotherapy for mass-type lesions

Background: The purpose of this study was to compare the accuracy of volumetric (3D) measurements with that of unidimensional (1D) measurements by response evaluation criteria in solid tumors 1.1 (RECIST 1.1) in patients with breast cancer before and after neoadjuvant chemotherapy. Methods: The study included 48 patients with breast cancer who underwent neoadjuvant chemotherapy. Dynamic contrast-enhanced magnetic resonance imaging was performed before the first cycle of chemotherapy and after the completion of the planned chemotherapy. The longest diameter and volume of each target lesion were measured using a TeraRecon Aquarius workstation (San Mateo, CA). Response was assessed both by using the RECIST 1.1 and volumetric criteria. Histologic response was assessed using the Sataloff criteria. The agreements between the two measures and the histologic response were analyzed statistically. Results: In monitoring the response to neoadjuvant chemotherapy, the 1D and 3D measurements showed "good agreement" (κ = 0.610) for the treatment response categories and "moderate agreement" (κ = 0.565) for the responder/non-responder categories. Disagreement was observed in 9 out of 48 comparisons (18.75 %). The percent agreement of the 1D measurement of residual lesions (79.17 %) with the pathology was higher than that by volumetric measurement (70.83 %), but there was no statistically significant difference (p = 0.35). Both the 1D (rho = 0.67, p < 0.0001) and 3D measurements (rho = 0.52, p < 0.0001) showed a moderate degree of linear correlation with the pathologic diameter of residual lesions. Conclusion: There was generally good agreement between the 1D and 3D measurements and moderate predictive value using either approach for predicting pathological response. © 2012 The Japanese Breast Cancer Society.