Risk assessment of thin melanomas

Prof Dr Bart Neyns, medical oncologist at UZ Brussels, and Dr Jolien Kessels, dermatologist and researcher in his team, presented findings from a retrospective study on early-stage melanoma at EADO 2025. The study focused on improving prognosis prediction for patients with thin melanomas, particularly those classified as pT3a or lower, since many metastatic melanoma cases begin with such early-stage diagnoses.

The study evaluated the Merlin test, a molecular diagnostic tool that categorises early melanomas into high- or low-risk groups for progression. Results demonstrated that the Merlin test adds prognostic value beyond sentinel node status. Patients with both a positive sentinel node and a high-risk Merlin score had significantly worse outcomes, reinforcing the test’s clinical utility.

Building on these findings, the team announced the launch of a prospective trial. This trial will include high-risk primary cutaneous melanoma patients without detectable metastases. Criteria include pT1b to pT3a with a high-risk Merlin score, or pT3b to pT4b regardless of Merlin score. Patients will receive one neoadjuvant dose of pembrolizumab (400 mg over six weeks) before sentinel node biopsy. The goal is to assess whether early immunotherapy can reduce positive sentinel node rates and better identify those needing intensive follow-up.

Prof Dr Neyns highlighted the potential for this test to reassure low-risk patients and personalise care. Supported by previous large-scale data from other studies, the Merlin test may help reduce overtreatment and focus attention on patients truly at risk. The upcoming prospective study aims to validate this strategy within the Belgian population.