Restaging [ 18 F] fludeoxyglucose positron emission tomography/computed tomography scan in recurrent cutaneous squamous cell carcinoma: Diagnostic performance and prognostic significance.

Background: There are no specific recommendations for [ ¹⁸ F] fludeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in assessing recurrent cutaneous squamous cell carcinoma (cSCC).
Objective: To evaluate FDG-PET/CT in recurrent cSCC.
Methods: FDG-PET/CT scans were retrospectively reviewed. Sites of abnormal uptake were noted and correlated with biopsy/histopathology studies, where available, and with follow-up imaging or clinical data in others. Comparison with available CT/magnetic resonance imaging was performed. The prognostic significance of PET/CT parameters was evaluated, and PET/CT-based change in management was recorded.
Results: A total of 115 FDG-PET/CT scans were analyzed in 100 consecutive patients with cSCC. Of these, 96 (84%) scans were positive for recurrence, and 25 showed distant metastases. PET/CT detected unsuspected disease sites in 39 of 115 scans (34%), locoregional disease in 14, distant metastases in 11, both locoregional disease and distant metastases in 8, additional local cutaneous disease in 5, and second malignancy in 1. Comparison of 78 PET/CT scans with available CT/magnetic resonance imaging showed 37 additional abnormalities on 23 PET/CT scans, predominantly including skin/subcutaneous lesions and nodes. PET/CT led to change in management in 28% of patients. On univariate/multivariate analysis, increased number of FDG-positive lesions and lung metastases on PET/CT was associated with increased risk of death/disease progression.
Limitations: Retrospective study.
Conclusions: FDG-PET/CT was sensitive in detecting recurrent disease in cSCC, led to change in management for 28% of patients, and proved to be of prognostic value.
(Copyright © 2019 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)