Combining standardized uptake value of FDG-PET and apparent diffusion coefficient of DW-MRI improves risk stratification in head and neck squamous cell carcinoma

Objectives To assess the independent prognostic value of standardized uptake value (SUV) and apparent diffusion coefficient (ADC), separately and combined, in order to evaluate if the combination of these two variables allows further prognostic stratification of patients with head and neck squamous cell carcinomas (HNSCC). Methods Pretreatment SUV and ADC were calculated in 57 patients with HNSCC. Mean follow-up was 21.3 months. Semiquantitative analysis of primary tumours was performed using SUV maxT/B , ADC mean , ADC min and ADC max . The prognostic value of SUV maxT/B , ADC mean , ADC min and ADC max in predicting disease-free survival (DFS) was evaluated with log-rank test and Cox regression models. Results Patients with SUV maxT/B ≥5.75 had an overall worse prognosis ( p = 0.003). After adjusting for lymph node status and diameter, SUV maxT/B and ADC min were both significant predictors of DFS with hazard ratio (HR) = 10.37 (95 % CI 1.22–87.95) and 3.26 (95 % CI 1.20–8.85) for SUV maxT/B ≥5.75 and ADC min ≥0.58 × 10 −3 mm 2 /s, respectively. When the analysis was restricted to subjects with SUV maxT/B ≥5.75, high ADC min significantly predicted a worse prognosis, with adjusted HR = 3.11 (95 % CI 1.13–8.55). Conclusions The combination of SUV maxT/B and ADC min improves the prognostic role of the two separate parameters; patients with high SUV maxT/B and high ADC min are associated with a poor prognosis. Key Points • High SUV maxT/B is a poor prognostic factor in HNSCC • High ADC min is a poor prognostic factor in HNSCC • In patients with high SUV maxT/B , high ADC min identified those with worse prognosis