Multiparametric MRI for prediction of treatment response to neoadjuvant FOLFIRINOX therapy in borderline resectable or locally advanced pancreatic cancer

Objectives To identify multiparametric MRI biomarkers to predict the tumor response to neoadjuvant FOLFIRINOX therapy in patients with borderline resectable (BR) or locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC). Methods From May 2016 to March 2018, adult patients with BR or LA PDAC were prospectively enrolled in this study. They received eight cycles of FOLFIRINOX therapy and underwent multiparametric MRI twice (at baseline and after the second cycle). MRI evaluations included dynamic contrast-enhanced MRI, intravoxel incoherent motion diffusion-weighted imaging, and assessment of T2* relaxivity (R2*) and the change in T1 relaxivity (Delta R1, equilibrium phase R1 minus non-enhanced R1) of the tumors. Factors to predict the responders determined by the best overall response during FOLFIRINOX therapy and those to predict progression-free survival (PFS) and overall survival (OS) were evaluated using multivariable logistic regression and the Cox proportional hazard model. Results Forty-one patients (mean age, 60.3 years +/- 9.3; 24 men) were included. Among the clinical and MRI factors, the baseline Delta R1 (adjusted odds ratio, 31.07;p= 0.008) was the only independent predictor for tumor response. The baseline Delta R1 was also an independent predictor for PFS (adjusted hazard ratio, 0.40;p= 0.033) along with R0 resection. The use of a cutoff Delta R1 value of >= 1.31 s(-1)enabled prognostic stratification (median PFS, 16.0 months vs.10.0 months;p= 0.029; median OS, 34.9 months vs. 16.6 months;p= 0 .023, respectively). Conclusions The baseline tumor Delta R1 value may be useful to predict tumor response and survival in patients with BR or LA PDAC receiving FOLFIRINOX neoadjuvant therapy.