Chen Yunbin MD, Abstract Co-Author: Nothing to Disclose

Dechun Zheng MS, Presenter: Nothing to Disclose

Xiangyi Liu BS, Abstract Co-Author: Nothing to Disclose

Luying Xu BS, Abstract Co-Author: Nothing to Disclose

Weibo Chen MSc, Abstract Co-Author: Nothing to Disclose

Queenie Chan PhD, Abstract Co-Author: Nothing to Disclose

Jianji Pan, Abstract Co-Author: Nothing to Disclose

To prospectively evaluate the feasibility of acquiring serial DCE-MRI in early predicting chemoradiotherapy (CRT) response of nasopharyngeal carcinoma (NPC).

Thirty-five patients with stage III and IV NPC underwent 5 MRI scans at baseline (Pre-Tx), 3 days (Day3-Tx) and 20 days (Day20-Tx, one cycle of NAC) after neoadjuvant chemotherapy (NAC) initiation, 6 days after radiotherapy initiation (Day50-Tx) and at terminal of CRT (Post-Tx) respectively. Kinetic parameters (Ktrans, Kep, Ve, and Vp) were calculated based on extended Tofts model. Tumor response after NAC and definite CRT were assessed and categorized respectively into stable disease (SD), partial response (PR) or completed response (CR) based on WHO criteria. Kinetic parameters at Pre-Tx and Day20-Tx and their changes during chemo-radiotherapy Δ (0-X) were compared between responders and non-responders using student t test or Mann-Whitney U test. The diagnosis accuracies of kinetic parameters were calculated with receiver operating characteristic curve (ROC) analysis.  

A total of 146 scans were acquired. Two patients withdrew due to serious motion. After NAC, 8 of 33 patients were categorized into PR; and 21 of 31 into CR at the end of CRT. The PR group after NAC had significantly higher median Ktrans and Kep values at Pre-Tx (p<0.05); and higher ΔKtrans(0-3) and ΔKep(0-3) values (p<0.05) too. The CR group after CRT exhibited lower Ktrans at Day20-Tx (p=0.001) and higher ΔKtrans (0-20) (p=0.002), respectively (Graph 1). The ΔKtrans(0-3) and ΔKep(0-3) yielded higher diagnosis accuracy than pretreatment Ktrans and Kep (0.845 VS 0.810, 0.887 VS 0.785, respectively), while pre-radiotherapy Ktrans at Day20-Tx yielded similar diagnosis accuracy with ΔKtrans (20-0) (0.894 VS 0.881) (graph 2).  For the above parameters, we gained high sensitivity (85.7 to 87.5) and moderate to high specificity (60 to 83.3) to sift non-responders from responders. ΔKtrans(0-50) showed no significance difference.            

This pioneering DCE-MRI based study showed that early non-invasive monitoring of NPC therapy response was feasible. Particularly, pretreatment Ktrans and Kep and earlier changes during therapy were valuable imaging predictors of NPC.

Serial DCE-MRI scan and analysis during CRT process is useful strategy to evaluate and predict tumor response to NAC and CRT in NPC. Ktrans and Kep might become potential prognostic indicators of NPC.

Yunbin, C, Zheng, D, Liu, X, Xu, L, Chen, W, Chan, Q, Pan, J, Application of Serial Dynamic Contrast-enhanced Magnetic Resonance Imaging (DCE-MRI) in Early Predicting Chemoradiotherapy Response of Nasopharyngeal Carcinoma.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13018400.html