Value of apparent diffusion coefficient prior to neoadjuvant therapy is a predictor of histologic response in patients with borderline resectable pancreatic carcinoma.

Abstract

The parameters to predict histological response to neoadjuvant therapy remain controversial in borderline resectable pancreatic carcinoma (BRPC). Twenty-four patients who underwent diffusion-weighted magnetic resonance imaging (DW-MRI) prior to expected neoadjuvant chemo/chemoradiotherapy and surgery were reviewed retrospectively. Analyses for correlation between percent tumor cell destruction and the following was performed to investigate the parameter and cut off value: tumor size, whole tumor apparent diffusion coefficient (ADC) value of DW-MRI, maximum standardized uptake value of 18 F-fluorodeoxyglucose positron emission tomography, carbohydrate antigen 19-9, and their change ratios. The selected parameter was assessed for prediction ability of the histological response to neoadjuvant chemo/chemoradiotherapy and R0 curability. Pre-treatment ADC value was correlated with tumor cell destruction rate among all parameters (R=0.625, P=0.001). The ADC cut-off value for discriminating between nonresponders (grade I) and responders (grade IIa and more) after treatment was determined as 1.20×10-3 mm2 /s and the sensitivity, 100%; specificity, 75%; accuracy, 83% for responder, and the sensitivity, 100%; specificity, 63%; accuracy, 71% for R0 curability. Pre-treatment ADC value appeared to be a predictor of R0 curability in BRPC patients because of effective histological response to neoadjuvant therapy, and there was a significant correlation between the baseline ADC value and histological tumor cell destruction rate.