Oesophageal squamous cell carcinoma: histogram-derived ADC parameters are not predictive of tumour response to chemoradiotherapy

ObjectivesTo evaluate correlations between tumour response to definitive chemoradiotherapy (CRT) in oesophageal squamous cell carcinoma (SCC) and histogram-derived apparent diffusion coefficient (ADC) parameters on diffusion-weighted MR images.MethodsForty patients with clinical T3-4 oesophageal SCC underwent concurrent CRT. MR examination at 3 T was performed 1-3 days prior to CRT. Readout-segmented echo-planar diffusion imaging was used to acquire ADC maps. Pre- and post-treatment CT examinations were performed. Histogram parameters (mean, 10th, 25th, 50th, 75th, 90th percentiles, skewness and kurtosis) of the ADC values were compared with post-treatment disease status based on RECIST and the tumour regression ratio.ResultsNone of the ADC parameters showed significant correlation with post-treatment status (range of Spearman's values - 0.19 to 0.14, range of p values 0.22-0.47) or tumour regression ratio (range of Spearman's values - 0.045 to 0.18, range of p values 0.26-0.96). Neither progression-free survival (PFS) (p = 0.17) nor overall survival (OS) (p = 0.15) was significantly different between the two groups corresponding to the lower (< median) and upper arms ( median) of the mean ADC values.ConclusionsHistogram-derived pretreatment ADC parameters were not predictive imaging biomarkers for tumour response to CRT in patients with oesophageal SCC.Key Points center dot Apparent diffusion coefficient (ADC) values are derived from diffusion-weighted MR imaging.center dot High-resolution diffusion-weighted images are generated by readout-segmented echo-planar diffusion imaging.center dot Readout-segmented echo-planar diffusion-weighted imaging enabled evaluation of ADC parameters.center dot Pretreatment ADC parameters do not predict chemoradiotherapy response in patients with oesophageal carcinoma.