Whole-Body Imaging for the Primary Staging of Melanomas—A Single-Center Retrospective Study

SIMPLE SUMMARY: In melanoma, distant metastasis is frequent. To assess the state of metastasis formation at diagnosis, a common method employed is an invasive sentinel lymph node biopsy. However, in recent years, the use of non-invasive positron emission tomography combined with computed tomography (PET/CT) imaging for primary staging, especially in thick primary melanoma, has significantly increased. This study aims to elucidate the value of whole-body imaging for staging at melanoma diagnosis and to identify when whole-body imaging is currently used for primary staging, as well as evaluating its diagnostic precision. Furthermore, its effects on the subsequent diagnostic and therapeutic procedures should be determined to better understand the possible future implications. ABSTRACT: Background: Melanoma staging at diagnosis predominantly depends on the tumor thickness. Sentinel lymph node biopsy (SLNB) is a common tool for primary staging. However, for tumors of >4 mm with ulceration, 3D whole-body imaging and, in particular, Fluor-18-Deoxyglucose positron emission tomography combined with computed tomography ((18)F-FDG-PET/CT), is recommended beforehand. This study aimed to investigate the real-world data of whole-body imaging for initial melanoma staging and its impact on the subsequent diagnostic and therapeutic procedures. Methods: In this retrospective single-center study, 94 patients receiving (18)F-FDG-PET/CT and six patients with whole-body computed tomography (CT) scans were included. The clinical characteristics, imaging results, and histologic parameters of the primary tumors and metastases were analyzed. Results: Besides the patients with primary tumors characterized as pT4b (63%), the patients with pT4a tumors and pT3 tumors close to 4 mm in tumor thickness also received initial whole-body imaging. In 42.6% of the patients undergoing (18)F-FDG-PET/CT, the imaging results led to a change in the diagnostic or therapeutic procedure following on from this. In 29% of cases, sentinel lymph node biopsy was no longer necessary. The sensitivity and specificity of (18)F-FDG-PET/CT were 66.0% and 93.0%, respectively. Conclusion: Whole-body imaging as a primary diagnostic tool is highly valuable and influences the subsequent diagnostic and therapeutic procedures in a considerable number of patients with a relatively high tumor thickness. It can help avoid the costs and invasiveness of redundant SLNB and simultaneously hasten the staging of patients at the time of diagnosis.