Prediction of pathologic responders to neoadjuvant chemoradiotherapy by diffusion-weighted magnetic resonance imaging in locally advanced esophageal squamous cell carcinoma: a prospective study

This study aims to investigate the role of diffusion-weighted magnetic resonance imaging (DW-MRI) in ESCC patients receiving neoadjuvant concurrent chemoradiotherapy (CCRT), and the efficacy of apparent diffusion coefficient (ADC) values in predicting pathologic response to neoadjuvant CCRT. Twenty-eight locally advanced ESCC patients treated with neoadjuvant CCRT followed by radical resection were prospectively enrolled. DW-MRI was recommended to be performed within 2 weeks before and 4-6 weeks after neoadjuvant CCRT. The calculated ADCs pre- (ADC1) and post- (ADC2) neoadjuvant CCRT, the definite (ΔADC) and percentage changes (ΔADC%) were analyzed for the efficacy of predicting pathologic response to neoadjuvant CCRT. Twenty patients had been identified as responders (tumor regression grade 1-2). Among them, ADC2 (3.02 ± 0.84 vs. 2.12 ± 0.44 × 10-3 mm2/s, P = 0.001) and ΔADC (1.22 ± 0.78 vs 0.64 ± 0.26 × 10-3 mm2/s, P = 0.007) were significantly higher than those of nonresponders (tumor regression grade: 3-5). Receiver operating characteristic analysis revealed that ADC2 exhibited an overall accuracy of in 71.4% in predicting pathologic response, with a sensitivity of 60.0%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 50.0%, when 3.04 × 10-3 mm2/s was used as the cutoff value. ADC value could be useful in predicting pathologic response to neoadjuvant CCRT in ESCC patients. High postneoadjuvant CCRT ADC is a predictive indicator for good response.