Outcome of Clinical Stage III Melanoma Patients with FDG-PET and Whole-Body CT Added to the Diagnostic Workup

BACKGROUND: Combined whole-body FDG-PET and CT provide the most comprehensive staging of melanoma patients with palpable lymph node metastases (LNM). The aim of this study is to analyze survival of FDG-PET and CT negative or positive melanoma patients and to assess which factors have independent prognostic impact on survival of these patients. METHODS: Patients with palpable and histologically or cytologically proven LNM of melanoma, referred to participating hospitals for examination with FDG-PET and CT, were selected from a previous study. Melanoma-specific survival (MSS) and disease-free period (DFP) were analyzed for FDG-PET and CT positive and negative patients using the Kaplan-Meier method. Cox-regression analysis was performed to analyze which patient or melanoma characteristics had significant impact on MSS or DFP. RESULTS: For all 252 patients 5-year MSS was 38.2 %. For FDG-PET and CT negative and positive patients 5-year MSS was 47.6 and 16.9 %, respectively. Disease-free period for FDG-PET and CT negative patients was 46.0 % after 5 years. Gender, a positive FDG-PET and CT, LNM in axilla compared to head or neck, and presence of extranodal growth were independent factors for worse MSS in all patients. Positive FDG-PET and CT was the most important prognostic factor for MSS with a hazard ratio of 2.54 (95 % CI, 1.55-4.17, P < 0.001). CONCLUSIONS: Staging melanoma patients with palpable LNM is more accurate when whole-body FDG-PET and CT is added to the diagnostic workup. Hence, FDG-PET and CT, preferably combined, are indicated in the staging of clinical stage III melanoma patients