Diffusion-weighted magnetic resonance imaging for early response assessment of chemoradiotherapy in patients with nasopharyngeal carcinoma.
OBJECTIVE
To prospectively evaluate the feasibility of diffusion-weighted magnetic resonance imaging (DWI) for monitoring early treatment response to chemoradiotherapy (CRT) of nasopharyngeal carcinoma (NPC).


METHODS
Thirty-one patients with stage III and IV NPC were enrolled in this study from February 2012 to November 2012．T2-weighted and DWI sequences with diffusion factor of 0 and 800mm²/s were performed using a 3.0 T Philips Achieva TX scanner at baseline and 3 days, 20 days (after the first cycle of chemotherapy), 50 days (6 days after radiotherapy initiation) after neoadjuvant chemotherapy (NAC) initiation. The diameter of each primary lesion and target metastatic lymph node before and after the first cycle of NAC was measured and classified into stable disease (SD), partial response (PR) or completed response (CR) based on RECIST 1.1. The apparent diffusion coefficient (ADC) values and changes compared to baseline at each time point were compared between responders (CR and PR) and non-responders (SD). The rates of residual at the end of CRT were compared between these two groups.


RESULTS
A significant increase in ADC was observed at each stage of therapy (P=.001) in lesions of primary and metastatic. The ADC values (ADC), ADC changes (ΔADC) and percentage ADC changes (Δ%ADC) of day 20 in responders were significantly higher than in non-responders for both primary lesions (p=.005, p=.006, p=.008, respectively) and metastatic lymph nodes (p=.002, p=.002, p=.003). Non-responders showed a higher rate of residual for both primary lesions (p=.008) and metastatic lymph nodes (p=.024) than responders.


CONCLUSIONS
DW MR imaging allows for detecting early treatment response of NPC. Patients with high ADC values and large ADC increase early after NAC initiation tended to respond better to CRT. Thus, accessing the curative effect of NAC in advanced NPC provides the opportunity to adjust following CRT regimen.
Department of Radiology, Fujian Medical University Teaching Hospital, Fujian Provincial Cancer Hospital, 350014, Fujian, P.R. China. Electronic address: Yunbinchen@126.com.
YunBin
Y
Chen
Department of Radiology, Fujian Medical University Teaching Hospital, Fujian Provincial Cancer Hospital, 350014, Fujian, P.R. China.
Xiangyi
X
Liu
Department of Radiology, Fujian Medical University Teaching Hospital, Fujian Provincial Cancer Hospital, 350014, Fujian, P.R. China.
Dechun
D
Zheng
Department of Radiation Oncology in Head and Neck, Fujian Medical University Teaching Hospital, Fujian Provincial Cancer Hospital, 350014, Fujian, P.R. China.
Luying
L
Xu
Department of Radiation Oncology in Head and Neck, Fujian Medical University Teaching Hospital, Fujian Provincial Cancer Hospital, 350014, Fujian, P.R. China.
Liang
L
Hong
Department of Radiation Oncology in Head and Neck, Fujian Medical University Teaching Hospital, Fujian Provincial Cancer Hospital, 350014, Fujian, P.R. China.
Yun
Y
Xu
Department of Radiation Oncology in Head and Neck, Fujian Medical University Teaching Hospital, Fujian Provincial Cancer Hospital, 350014, Fujian, P.R. China.
Jianji
J
Pan
D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma; D059248:Chemoradiotherapy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000473:pathology / Q000628:therapy*; D009367:Neoplasm Staging; D011446:Prospective Studies; D016896:Treatment Outcome
Chemoradiotherapy; Diffusion-weighted MRI; Nasopharyngeal carcinoma; Treatment assessment