Prognostic value of 18F-FDG PET/CT and MRI features in patients with high-risk and very-high-risk cutaneous squamous cell carcinoma

Objectives: This study aimed to evaluate the prognostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and magnetic resonance imaging (MRI) features in patients with high-risk and very-high-risk cutaneous squamous cell carcinoma (cSCC). Methods: This study included 54 consecutive patients with surgically resected primary high-risk and very-high-risk cSCC who underwent preoperative FDG-PET/CT and/or MRI. Among them, 14 patients (26%) had recurrences. We retrospectively reviewed the FDG-PET/CT (n = 34) and MRI (n = 48) and investigated the clinical significance and prognostic value of imaging features in cSCC. Results: On FDG-PET/CT, the maximum standardized uptake value (SUVmax) of the primary tumor (13.0 ± 6.4 vs. 6.9 ± 5.3, p < 0.05) was higher in cSCC with recurrence than in cSCC without recurrence. On MRI, the maximum diameter of the lesion (46.8 ± 24.1 mm vs 30.4 ± 17.0 mm, p < 0.05) and the frequency of muscle/tendon/bone invasion (42% vs 11%, p < 0.05) were significantly greater in cSCC with recurrence than in cSCC without recurrence. In the univariate analysis, prognostic factors for recurrence were SUVmax of the primary tumor (p < 0.01), the maximum diameter of the lesion (p < 0.05), and depth of invasion (p < 0.05). The areas under the receiver operating characteristic curves of the SUVmax (0.78) were superior to those of the maximum diameter (0.71) and depth of invasion (0.60). Conclusions: SUVmax, maximum diameter, and depth of invasion were useful parameters for prognostic factors predicting recurrence in patients with high-risk and very-high-risk cSCC. Advances in knowledge: SUVmax represents a prognostic factor.