Early response to chemoradiotherapy for nasopharyngeal carcinoma treatment: Value of dynamic contrast-enhanced 3.0 T MRI.

Objective: To prospectively evaluate the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) value for predicting early nasopharyngeal carcinoma (NPC) chemoradiotherapy (CRT) response.

Methods: Forty-two patients with advanced NPC were recruited and received three DCE-MRI exams before treatment (Pre-Tx), as well as 3 days (Day 3-Tx) and 40 days (Day 40-Tx) after chemotherapy initiation (two neoadjuvant chemotherapy cycles, NAC). We used DCE-Tool to measure primary tumor kinetic parameters (K(trans) , Kep , ve , and vp ) using the extended Tofts model. Kinetic parameters and corresponding changes were compared between responders and nonresponders after NAC or CRT treatment using Student's t or Mann-Whitney U tests.

Results: Response to two NAC cycles correlated with short-term local control (P = 0.01). Compared to the nonresponder group, the responder group presented with significantly larger ΔK(trans) (0-3) , ΔKep(0-3) , and Δvp(0-3) values after NAC (P < 0.05). The complete response group after CRT exhibited significantly lower K(trans) (Day 40-Tx) and larger ΔK(trans) (0-3) values than the residual group (P = 0.05). High sensitivity (range: 74.1%-90%) and moderate-to-high specificity (range: 50%-84.3%) distinguished nonresponders from responders grouping after NAC or CRT, with diagnostic efficiency ranging from 69.3%-88%.

Conclusions: Our study showed kinetic parameter changes earlier after chemotherapy were potential markers for NPC patients receiving CRT therapy following NAC.