Analysis of pairwise correlations in multi-parametric PET/MR data for biological tumor characterization and treatment individualization strategies
OBJECTIVE The purpose of this study was to determine whether pretreatment quantitative and visual parameters seen on PET/CT using (18)F-FDG add prognostic information for clinical staging in patients with head and neck cancer. MATERIALS AND METHODS We enrolled 108 patients with histologically proven oral, oropharyngeal, hypopharyngeal, and laryngeal squamous cell carcinomas who underwent FDG PET/CT before treatment and, later, definitive therapy in our study. PET/CT parameters-maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and uptake pattern (sphere-shaped or ring-shaped)-were recorded. The prognostic value of these parameters was evaluated using univariate and multivariate Cox regression analyses. RESULTS In the univariate analysis, all of the FDG PET/CT parameters--SUVmax (> 10 g/mL) of the primary tumor, MTV (> 20 cm(3)), TLG (> 70 g), and uptake pattern (ring-shaped)--were significantly associated with negative effects on disease-specific survival (DSS) and disease-free survival (DFS). In the multivariate analysis, the MTV and uptake pattern remained associated with DSS after corrections for the Union for International Cancer Control (UICC) stage and definitive therapy (p = 0.023 and < 0.001, respectively). Another multivariate model that included MTV as a continuous variable, uptake pattern, and UICC stage showed that the uptake pattern remained significantly associated with DSS, whereas the association between DSS and MTV was not significant (p < 0.001 and = 0.332, respectively). CONCLUSION Our data indicate that the pretreatment PET/CT parameters had prognostic value. In particular, a qualitative factor, uptake pattern, provided better prognostic information to the clinical staging of head and neck squamous cell carcinomas than the other PET/CT parameters.