Predictive value of diffusion-weighted magnetic resonance imaging during chemoradiotherapy for head and neck squamous cell carcinoma

To evaluate diffusion-weighted (DWI) magnetic resonance imaging (MRI) for treatment prediction during chemoradiotherapy (CRT) of head and neck squamous cell carcinoma (HNC). Thirty patients with HNC underwent echo-planar DWI and anatomical MRI before and 2 and 4 weeks into CRT. Patient follow-up lasted 2 years post-CRT. Tumour ADC (Delta ADC) and volume changes (Delta V) between baseline, and 2 and 4 weeks' follow-up were compared for lesions with recurrence versus complete remission (CR) using a Mann-Whitney U test. The predictive value of the Delta ADC and Delta V for locoregional control (LRC) was examined with the Kaplan-Meier method. The study was approved by the local ethics committee. All patients gave written informed consent. The Delta ADC in primary tumours and nodal metastases, 2 and 4 weeks after the start of CRT, was significantly lower in lesions with post-CRT recurrence than in lesions with CR (Delta ADC(2 weeks) and Delta ADC(4 weeks) for primary tumours, relative to nodal metastases: p < 0.0001). The Delta V only showed a significant difference for primary tumours at 2 weeks (Delta V-2 weeks: p = 0.03). The Delta ADC correlated significantly with 2-year LRC (p < 0.001); the Delta V did not (p > 0.05). DWI during CRT for HNC allows more accurate response prediction than anatomical imaging, correlating significantly with 2-year LRC.