The use of FDG-PET/CT to detect early recurrence after resection of high-risk stage III melanoma.

Abstract

The role of surveillance imaging in high-risk stage III melanoma patients after complete surgical resection remains controversial, and with the advent of adjuvant therapy, it may also be expanded. Therefore, we evaluated two fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) protocols in two cohorts. Cohort 1 (n = 35) focused on surveillance in asymptomatic patients (before approval and reimbursement of adjuvant therapy) and was assigned to 5x FDG-PET/CT's after surgery: one every 6 months for 2 years, with one final scan after 3 years. Cohort 2 (n = 42) was assigned to one screening FDG-PET/CT, which took place in between surgery and the start of adjuvant treatment. In cohort 1 (median follow-up: 33 months), 12 patients (34.3%) developed recurrence detected by FDG-PET/CT, of which 7 (20.0%) were detected with the first scan. Sensitivity and specificity were 92.3% and 100%, respectively. In cohort 2, recurrence was suspected on nine scans (21.4%) and four (9.5%) were true positive. The number of scans needed to find one asymptomatic recurrence were 8.8 and 10.5 in cohort 1 and 2, respectively. FDG-PET/CT is a valuable imaging tool to detect recurrence in stage III melanoma, even shortly after surgery. A surveillance FDG-PET/CT protocol after surgery or a screening PET/CT before adjuvant therapy should be considered.