Efficacy of FDG PET/CT for diagnosing synchronous tumors and metastases in head and neck tumors: Initial results and evaluation

Objectives The aim of this study is to determine whether FDG PET/CT provides an earlier diagnosis of thoracic synchronous tumors and distant metastases.

Methods We retrospectively reviewed the files of 90 patients distributed in 2 groups according to the staging strategy. The first group (G1) included patients explored in 2009 who benefited from a classic assessment including a fibroscopy, a panendoscopy, a contrast-enhanced CT scan (ceCT) of the neck area and a chest ceCT. Starting in Jan 2010, a PET/CT was added in the second group (G2), including a non-enhanced full dose breath-hold chest CT in place of the chest ceCT. There were no statistical differences in terms of age, sex-ratio, tumor location, T and N stage across the 2 groups.

Results Overall results with regard to the nodal and distant staging, were classified according to the probability of malignancy of the anomalies that were described in the clinical reports: Probably malignant 7,7% in G1 Vs 13,7% in G2 ; probably benign 21,2% (G1) Vs 13,7% (G2);absence of lesion 44,2% (G1) Vs 57,9% (G2); equivocal lesions 27% (G1) Vs 5,3% (G2). Considering distant metastases and synchronous cancers, none were detected at diagnosis in G1 Vs in 13,7 % of the patients in G2. After a 1 year-follow-up for the group I, there were 2 TP, 32 TN, 1 FN and 1 FP results. Sensitivity and specificity were thus 67% and 95%, respectively. With a shorter follow up in group II, there were 6 TP, 24 TN, 3 FP and 0 FN. Sensitivity and specificity were thus 100% and 88%, respectively.

Conclusions These preliminary results seem to indicate that a strategy that includes FDG PET/CT at diagnosis improves the detection rate of synchronous tumors and distant metastases, while decreasing the number of undetermined findings. It is however associated with a lower specificity and the additional cost has also to be considered