Rôle de la TEP FDG dans l’évaluation de l’extension locorégionale et à distance du mélanome

Abstract

FDG PET/CT is a relevant examination for patients with high-risk melanoma. For early stages with thickness ≥ 1mm, lymph node ultrasound, and when negative, lymphoscintigraphy for determination of sentinel lymph node, remain necessary. For more advanced stages, FDG PET can map the lesions and guide the therapeutic strategy, either with surgical management, or systemic therapy (or sometimes both). In patients with high-risk melanoma, it allows to detect relapses early, including in asymptomatic patients, with a potential impact on therapeutic decisions. Beside the detection of classical secondary localizations, FDG PET has the advantage of allowing whole-body imaging, the identification of soft tissue lesions, frequent in melanomas, as well as rarer sites of involvement, such as those of the gastro-intestinal tract. For the assessment of cerebral and leptomeningeal involvement, MRI remains mandatory. Evolutions in the therapeutic management of advanced melanomas, and the search for biomarkers to guide the therapeutic strategy, ask for more refined analyses of PET, with metabolic tumour volume analysis and radiomics. The combination of metabolic imaging data with biological and molecular data, and the development of new PET tracers may improve the assessment of prognosis and the prediction of response to therapies, in order to tailor the therapeutic strategy to each patient. Further studies are needed to consolidate the role of PET/CT in this disease for which numerous therapeutic innovations are emerging.