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

BACKGROUND

The parameters to predict histological response to neoadjuvant therapy remain controversial in borderline resectable pancreatic carcinoma (BRPC).

METHODS

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 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.

RESULTS

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  mm /s and the sensitivity, 100%; specificity, 75%; accuracy, 83% for responder, and the sensitivity, 100%; specificity, 63%; accuracy, 71% for R0 curability.

CONCLUSIONS

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.