Diagnostic accuracy of 18F-FDG-PET/CT in early and late stages of high-risk cutaneous malignant melanoma

Background The precise role of total body 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) in the clinical management of patients with cutaneous malignant melanoma (CMM) is not well established. Objective The purpose of this study was to investigate the diagnostic accuracy of PET/CT in early- and late-stage patients with high-risk CMM. Methods We retrospectively analysed various imaging, histopathological and clinical data from 97 patients also examined by PET/CT during a 5-year period (2007–2011). Three groups were assessed: stage I/II, resected stage III and unresectable stage III/stage IV. Results The median follow-up time of living patients was 43.48 ± 19.67 (15–142) months. We observed a high diagnostic accuracy in all stages (91.3%, 92.5% and 96.2% respectively). PET/CT appeared to be reliable diagnostic tool even for the detection of small lymph node metastases. PET/CT was informative in 14 of 19 cases wherein another imaging examination provided inconclusive results regarding lesion dignity. However, PET/CT was less suitable for properly evaluating the dignity of a lung lesion. A true positive scan was twice as likely in clinically negative patients with resected stage III disease than in patients with stage I/II disease (35.9% and 14.5%, P = 0.007). Conclusions These results confirm that PET/CT is an important diagnostic tool in the management of patients with high-risk CMM, but it cannot replace the standard of care examinations. More accurate clinicopathological and timing criteria must be defined to best utilize the advantages of this imaging method.