Extracapsular spread and FDG PET/CT correlations in oral squamous cell carcinoma

Area of Science:

• Oncology
• Nuclear Medicine
• Radiology

Background:

• Oral squamous cell carcinoma (OSCC) is a common malignancy.
• Accurate staging, particularly identifying extracapsular spread (ECS) in cervical lymph nodes, is crucial for treatment planning and prognosis.
• ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) is a valuable imaging modality in oncology.

Purpose of the Study:

• To evaluate the diagnostic performance of FDG PET/CT in detecting ECS in patients with OSCC.
• To correlate FDG PET/CT findings, specifically maximum standardized uptake values (SUVmax), with histologic confirmation of ECS.
• To assess the impact of ECS and SUVmax on patient survival outcomes.

Main Methods:

• Retrospective review of medical records for 80 patients with OSCC who underwent pre-operative FDG PET/CT.
• Histopathologic analysis of dissected cervical lymph nodes to confirm ECS.
• Statistical analysis including receiver operating characteristic (ROC) curve analysis to determine the optimal SUVmax cutoff for ECS detection.

Main Results:

• ECS was histologically confirmed in 60% of dissected necks and 55% of cervical levels.
• Significantly higher SUVmax values were observed in lymph nodes with ECS compared to those without (3.33±1.91 vs. 1.12±1.24, p<0.001).
• At an optimal SUVmax cutoff of 2.25, FDG PET/CT demonstrated 85% sensitivity and 88% specificity for detecting ECS. The area under the ROC curve was 0.864±0.045 (p<0.001).

Conclusions:

• FDG PET/CT is a reliable imaging technique for identifying ECS in OSCC.
• An elevated SUVmax (>2.25) on FDG PET/CT is associated with a higher risk of cervical lymph node metastasis and adverse 5-year disease-specific survival in OSCC patients.