Intratumoural heterogeneity measured using FDG PET and MRI is associated with tumour-stroma ratio and clinical outcome in head and neck squamous cell carcinoma

AIM: To evaluate the association between the tumourestroma ratio and intratumoural heterogeneity measured using 2-[F-18]-fluoro-2-deoxy-D-glucose (FDG) positron-emission tomography (PET) and magnetic resonance imaging (MRI), and further investigate the prognostic significance of imaging biomarkers in head and neck squamous cell carcinoma (HNSCC). MATERIALS AND METHODS: Textural-based imaging parameters of the primary tumour were extracted in 44 patients. In addition, the difference between the minimum and maximum apparent diffusion coefficient (ADC) values (ADCdiff) was calculated on MRI. The relationships between the tumourestroma ratio and imaging parameters were evaluated. The associations between imaging parameters and recurrence-free survival (RFS) were assessed using Cox proportional hazard regression models. RESULTS: Coarseness (r = -0.382) on PET and ADCdiff (r = 0.534) on MRI were significantly correlated with the proportion of stroma. The best imaging biomarkers for the 2-year RFS prediction were coarseness (AUC = 0.741) and ADCdiff (AUC = 0.779). Multivariate analysis showed that coarseness (hazard ratio = 10.549, 95% confidence interval = 2.544-43.748, p = 0.001) was an independent prognostic factor for RFS. CONCLUSION: Heterogeneity imaging parameters are significantly associated with the tumourestroma ratio. These imaging biomarkers may help to facilitate the risk stratification for tumour recurrence in HNSCC. (C) 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.