Cutaneous squamous cell carcinoma (cSCC) is the second most common skin malignancy. Computed tomography (CT) and/or MRI are commonly used for staging, however, the role of fluorine-18-fluorodeoxyglucose (18F-FDG)-PET is not clearly established. In this study, we evaluated 18F-FDG-PET/CT imaging for initial staging of cSCC.
18F-FDG-PET/CT scans performed in patients with newly diagnosed cSCC were reviewed retrospectively. Images were visually assessed for lesions and 18F-FDG uptake [standardized uptake value (SUV)] in primary and secondary sites was measured. Suspected lesions on 18F-FDG-PET/CT were correlated with histopathology when available, follow-up imaging or clinical data in others.
Twenty-three cSCC patients who underwent 18F-FDG-PET/CT at diagnosis were evaluated. Primary sites were in head/neck (n=21), chest (n=1), and foot (n=1). All patients had 18F-FDG-positive scans with a total of 51 18F-FDG-positive lesions. All primary lesions (n=24) were 18F-FDG-positive (SUV: 2.3–22.8; mean 10.2), and additional 27 18F-FDG-positive lesions, including 21 nodes, four cutaneous, one osseous and one lung lesion, were noted in 13 patients. Mean size of 18F-FDG-positive nodes was 0.9 cm (range: 0.4–2.5 cm), predominantly clinically impalpable. Pathology was available for 40/51 lesions; 31 sites positive for malignancy. SUV (mean±SD) was 9.2±6.2 for malignant and 2.7±1.2 for benign lesions. Sensitivity, positive predictive value, and accuracy of 18F-FDG-PET/CT scan were 100, 77.5, and 77.5%, respectively. 18F-FDG detected seven additional lesions in three patients, compared to CT/MRI. Overall, staging 18F-FDG-PET/CT detected nine prior unknown lesions in five patients that were proven metastatic disease by histopathology or follow-up; 18F-FDG-PET/CT modified management in 5/23 (21.7%) patients.
18F-FDG-PET/CT has high sensitivity in the detection of cSCC lesions, including small cutaneous and nodal disease, and has a potential role in initial staging and management.
Departments of aRadiology
cSurgery, Memorial Sloan Kettering Cancer Center
dDepartment of Radiology, Weill Cornell Medical College, New York, New York, USA
2017 SNMMI, Denver, CO and published as abstract – Mahajan S, Barker C, Pandit-Taskar N. FDG PET/CT in staging cutaneous squamous cell carcinoma. J Nucl Med. 2017;58(Suppl 1):121–121.
Correspondence to Neeta Pandit-Taskar, MD, Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY 10065, USA Tel: +1 212 639 3046; fax: +1 212 717 3263; e-mail: firstname.lastname@example.org
Received February 22, 2019
Received in revised form April 19, 2019
Accepted April 24, 2019