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

Abstract

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). 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. 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 mm²/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). 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. • 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.