Prognostic value of (18)F-fluorodeoxyglucose positron emission tomography, computed tomography and magnetic resonance imaging in oral cavity squamous cell carcinoma with pathologically positive neck lymph node

PURPOSE: To evaluate the prognostic value of preoperative neck lymph node (LN) assessment with (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET), computed tomography (CT), and magnetic resonance imaging (MRI) in oral cavity squamous cell carcinoma (OSCC) patients with pathologically positive LN. MATERIALS AND METHODS: In total, 47 OSCC patients with pathologically positive LN were retrospectively reviewed with preoperative (18)F-FDG PET and CT/MRI. All patients underwent surgical resection, neck dissection and postoperative adjuvant radiotherapy and/or chemotherapy between March 2002 and October 2010. Histologic correlation was performed for findings of (18)F-FDG PET and CT/MRI. RESULTS: Thirty-six (76.6%) of 47 cases were correctly diagnosed with neck LN metastasis by (18)F-FDG PET and 32 (68.1%) of 47 cases were correctly diagnosed by CT/MRI. Follow-up ranged from 20 to 114 months (median, 56 months). Clinically negative nodal status evaluated by (18)F-FDG PET or CT/MRI revealed a trend toward better clinical outcomes in terms of overall survival, disease-free survival, local recurrence-free survival, regional nodal recurrence-free survival, and distant metastasis-free survival rates even though the trends were not statistically significant. However, there was no impact of neck node standardized uptake value (SUV(max)) on clinical outcomes. Notably, SUV(max) showed significant correlation with tumor size in LN (p < 0.01, R(2) = 0.62). PET and CT/MRI status of LN also had significant correlation with the size of intranodal tumor deposit (p < 0.05, R(2) = 0.37 and p < 0.01, R(2) = 0.48, respectively). CONCLUSION: (18)F-FDG PET and CT/MRI at the neck LNs might improve risk stratification in OSCC patients with pathologically positive neck LN in this study, even without significant prognostic value of SUV(max).