Melanin-targeted [¹⁸F]-PFPN PET imaging for prognosticating patients with melanoma

Purpose: Positron emission tomography (PET) using [¹⁸F]-PFPN, a melanin-targeted imaging tracer, has excellent diagnostic performance in patients with melanoma. This study aimed to investigate its value in prognostication and determine predictors of progression-free survival (PFS) and overall survival (OS).

Methods: We reviewed melanoma patients who underwent [¹⁸F]-PFPN and [¹⁸F]-FDG PET from February 2021 to July 2022. Clinical characteristics, follow-up data, and the following [¹⁸F]-PFPN PET parameters were recorded: maximum standardized uptake value (SUV_max), whole-body melanotic tumoral volume (WBMTV), and whole-body total lesion melanin (WBTLM). Receiver operating characteristic (ROC), Kaplan-Meier and Cox regression analyses were performed.

Results: Seventy-six patients (47 men and 29 women; mean age, 57.99 ± 10.72 years) were included for analysis. Median follow-up was 12.0 months (range: 1-22 months). Eighteen patients died and 38 experienced progression. Median OS was 17.60 months (95% confidence interval, 15.89-19.31). In the ROC analysis, [¹⁸F]-PFPN PET parameters were superior to those of [¹⁸F]-FDG PET in prognosticating death and disease progression. PFS and OS were significantly better in patients with lower SUV_max, WBMTV, and WBTLM on [¹⁸F]-PFPN PET (log-rank, P < 0.05). In the univariate analyses, distant metastasis, SUV_max, WBMTV, and WBTLM were significantly associated with cumulative incidence of PFS and OS (P < 0.05). In the multivariate analysis, SUV_max was an independent predictor of PFS and OS.

Conclusions: [¹⁸F]-PFPN PET has a role in prognostication of melanoma patients. Patients with higher [¹⁸F]-PFPN SUV_max have worse prognosis.

Clinical trial registration: ClinicalTrials.gov, NCT05645484. Registered 9 December, 2022, https://clinicaltrials.gov/ct2/show/NCT05645484?cond=The+Prognostic+Value+of+18F-PFPN+PET+Imaging+in+Patients+With+Malignant+Melanoma&draw=2&rank=1.