Dynamic contrast-enhanced and diffusion-weighted MR imaging in early prediction of pathologic response to neoadjuvant chemotherapy in locally advanced gastric cancer

Purpose To investigate the efficacy of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for the early prediction of the pathologic response to neoadjuvant chemotherapy (NAC) in patients with locally advanced gastric cancer (LAGC). Methods Fifty patients with LAGC who were treated with NAC followed by radical gastrectomy were enrolled. Uncontrasted and DCE-MRI were performed within 1 week before NAC. According to tumor regression grading (TRG), patients were labeled as responders (TRG = 0 + 1) and non-responders (TRG = 2 + 3). Apparent diffusion coefficients (ADC) and DCE-MRI kinetics (K-trans, V-e, and K-ep) were compared between the two groups. Logistic regression analysis was performed to screen independent factors to predict the NAC efficacy. The relationship between MRI parameters and TRG was studied by Spearman's correlation analysis. Receiver-operating characteristic curve analyses were applied to evaluate the efficacy. Results ADC, K-trans, and K-ep values were higher in responders than in non-responders (p < 0.05) and correlated with TRG (p < 0.05). The ADC and K-ep values were independent markers for predicting TRG. The area under the curve, sensitivities, specificities of ADC, K-trans, K-ep, and ADC + K-ep were 0.813, 0.699, 0.709, 0.886;73.64%, 65.54%, 63.21%, 70.37%; 86.47%, 54.97%, 79.47%, 95.65%; respectively. ADC + K-ep demonstrated a higher efficacy than K-trans and K-ep (p = 0.012, 0.011), but without improvement compared with ADC (p > 0.05). Conclusion Both DWI and DCE-MRI can effectively predict the pathologic response to NAC in LAGC. A combination of ADC and K-ep increased the efficacy, and ADC is the most valuable imaging parameter.

Automated summary

This study aimed to investigate the early prediction of the pathologic response to neoadjuvant chemotherapy (NAC) in patients with locally advanced gastric cancer (LAGC) using diffusion-weighted imaging (DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The results showed that a combination of apparent diffusion coefficients (ADC) and K-ep increased the efficacy in predicting the pathologic response, with ADC being the most valuable imaging parameter.