Imaging melanoma: when and why. A proposal for a modern approach

Purpose The use of imaging by X-ray computed tomography and positron emission tomography, as well as Sentinel Lymph Node Biopsy for managing malignant melanoma is considered a standard of care for the work-up of patients with melanoma. This paper aims to summarize the evidences related to the use of X-ray computed tomography and positron emission tomography in the management of localized (stage I and II) and advanced (stage ≥ III) melanoma. Methods A systematic search in EMBASE and PUBMED databases—starting from 2011—was performed, using the following keywords: melanoma, skin cancer, metastasis, CT, imaging, PET/CT, sentinel node, sentinel node biopsy. Results A total of 130 papers were analyzed. After excluding case reports (12), anecdotal reports (7), low-quality studies (46), a total of 65 papers were evaluated. The results of the analysis can be summarized as follows: in the evaluation of nodal status, scintigraphic mapping of regional basin, followed by sentinel lymph node or complete lymph node dissection is nowadays considered the standard of care for the correct staging of the disease, whereas the therapeutic utility of preventive complete lymph node dissection is still under debate. Conclusion SLNB should always be offered to patients with melanoma thickness ≥ 1 mm, whereas for thickness ≤ 1 mm SLNB may be useful only in presence of definite risk factors in the primitive lesion. The use of cross-sectional imaging is always indicated for melanoma staging in advanced disease (stage III and higher), as well as in the evaluation of to treatment response, and during the surveillance for no evidence of disease patients. Finally, cross-sectional imaging should be used very carefully in low stages of the disease (stage I and low risk stage II), for the possible presence of FP results.