Clinical impact of positron emission tomography (PET) with (18F)fluorodeoxyglucose (FDG) in head and neck tumours

Value of fluoro-2-deoxy-D-glucose-positron emission tomography for detecting metastatic lesions in head and neck cancer

OBJECTIVES

The role of positron emission tomography (PET) scans in the staging of head and neck cancer (HNC) is unclear. The National Comprehensive Cancer Network guidelines do not recommend routine metastatic workup beyond physical examination, chest x-ray, and laboratory tests. The purpose of this report is to examine the accuracy of staging PET scans for detecting distant metastatic disease in patients with HNC.

METHODS

Retrospective review of 182 consecutive newly diagnosed HNC patients who had a staging PET scan at Thomas Jefferson University Hospital between 2003 and 2007.

RESULTS

The overall incidence of confirmed distant metastatic disease in this population was 5.0%. About 26 of the staging PET scans had areas suspicious for a metastatic lesion(s). Of total, 23 patients were further evaluated with imaging and/or biopsy, revealing 9 (39%) true positives, and 14 (60%) false positives. Of the 156 negative PET scans, there was 1 false negative and 155 true negatives. Thus, the sensitivity of PET was 90% and specificity was 92%. Positive predictive value was 39% and negative predictive value was 99.4%. No patients with pre-PET clinical stage I or II cancer had confirmed distant metastases. The only statistically significant predictor for metastatic disease was clinical stage IV versus all other stages (P=0.03).

CONCLUSIONS

Given the marked differences in the treatment of locally advanced/nonmetastatic HNC versus metastatic HNC, we recommend PET for clinical stage IV disease. Although the sensitivity, specificity, and negative predictive value rates were acceptable, the positive predictive value was suboptimal. Patients found to have a PET scan "positive" for metastatic disease require confirmatory imaging or ideally biopsy.

Clinical significance of combined assessment of the maximum standardized uptake value of F-18 FDG PET with nodal size in the diagnosis of cervical lymph node metastasis of oral squamous cell carcinoma

RATIONALE AND OBJECTIVES

This study aimed to elucidate the diagnostic accuracy of F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) for nodal involvement in oral squamous cell carcinoma (OSCC), and to reveal clinically useful factors to distinguish between true-positive (TP) and false-positive (FP) nodes.

MATERIALS AND METHODS

Thirty-eight patients with primary OSCC who underwent neck dissection were assessed. The diagnostic accuracy of F-18 FDG PET/CT was evaluated, and then compared with that of CT/ultrasonography (US). Furthermore, the association of the maximum standardized uptake value (SUVmax) and nodal size with the histopathologic findings was examined.

RESULTS

Sensitivity and specificity using F-18 FDG PET/CT were 77.1% and 97.3%, and those using CT/US were 72.9% and 98.9%, respectively. The SUVmax of TP nodes was significantly higher than that of FP nodes. Nodes with SUVmax >4.5 were pathologically confirmed as metastasis. Nodes with SUVmax ≤4.5 were further discriminated between TP and FP nodes by using the long axis diameters or the ratios of long to short axis diameter as clinical parameters. Positive correlation between the SUVmax and the short-axis diameter was found in TP nodes. The AUC obtained from the ROC curves of the SUVmax alone (AUC, 0.804) was improved by combination with the long-axis diameter (AUC, 0.867) or the short-axis diameter (AUC, 0.846), although no significant difference was found.

CONCLUSIONS

These results indicated that F-18 FDG PET/CT was potentially useful in diagnosing preoperative nodal state. Furthermore, combined assessment of SUVmax with nodal size could be significant in the identification of metastatic lymph nodes in OSCC patients.