Prognostic prediction of early oral squamous cell carcinoma using FDG-PET/CT.

Objectives: To evaluate utility of FDG-PET/CT for prognostic prediction of early oral squamous cell carcinoma (OSCC).

Methods: 127 patients (78 male, 49 female, mean age of 59.4 years old) of early OSCC (<T2N0M0), who had undergone FDG-PET/CT for pretherapeutic staging, were enrolled in this retrospective study. 61 and 66 patients were judged as clinical T1 and T2, respectively. Exclusion criteria were as follows: previous history of other malignant tumor within 5 years, cervical dissection, radiation therapy for head and neck area, hyperglycemia (>150mg/dl) before FDG injection, and insufficient clinical information in medical records. Three nuclear medicine physicians evaluated each PET/CT study with only the information that those patients had undergone for staging of early OSCC. FDG-avidity was judged in visual interpretation by consensus. For the tumors judged as FDG-avid, maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were calculated. Kaplan-Meier method and the log-rank test were used to compare disease free survival (DFS) between subgroups. Cox’s proportional hazards model was used for multivariate analysis.

Results: Patients with FDG-avid primary lesion had significantly shorter DFS than non-FDG-avid cases (p=0.037). Other semiquantitative parameters on PET/CT, age, sex, and clinical T stage did not show significant difference in DFS. Multivariate analysis revealed that only the SUVmax was an independent predictor of DFS (p=0.036).

Conclusion: FDG-avidity in visual interpretation and SUVmax of the primary lesion are useful for predicting DFS of early OSCC patients. Research Support: None.