Utility of FDG PET/CT in Restaging and Detection of Distant Metastases in Recurrent Head and Neck Carcinoma
Anjali Prakash, Nilendu C Purandare, Sneha Shah, Ameya D Puranik, Archi Agrawal, Gouri Pantvaidya, Sarbani Ghosh Laskar, Vanita Noronha, Kumar Prabhash, Venkatesh RangarajanObjectives:
To evaluate the role and clinical utility of FDG PET/CT in the detection of extrathoracic distant metastases (DM) in recurrent head and neck squamous cell carcinoma (HNSCC) and to identify high-risk clinical predictors for systemic spread.
Material and Methods:
Data of 500 patients with histopathologically proven recurrent HNSCC who underwent FDG PET/CT for restaging between January 2010 and June 2018 were analysed. Findings were validated by histopathology, follow-up imaging or multidisciplinary consensus. Statistical correlation was performed for various predictors of distant metastases, like initial TNM stage, primary site, disease-free interval (DFI), and clinical recurrent stage (crTNM). The impact of restaging PET/CT on management decisions was also studied.
Results:
DM were identified in 144/500 patients (28.8%), with 54 patients (10.8% of the total cohort) presenting with isolated extrathoracic metastases, which altered clinical management. FDG PET/CT demonstrated 100% sensitivity and 99.5% specificity for DM detection. Significant predictors for DM included advanced initial TNM stage, initial N-stage, shorter DFI, and advanced crTNM stage ( p < 0.05).
Conclusion:
There is a high incidence of distant metastases in recurrent HNSCC, with a significant proportion occurring as isolated extrathoracic disease. 18 F-FDG PET/CT significantly impacts management by unmasking systemic spread missed by regional CT protocols. We recommend that PET/CT should be used for restaging in a high-risk subset of head-neck cancer patients defined by advanced initial staging and a short disease-free interval