Aims
In-transit melanoma (ITM) occur in 5-10% of patients and has poor prognosis. Numerous lesions can limit surgical options and the role of systemic therapies is not well defined. We investigated the clinical outcomes of those treated with systemic therapies in a tertiary centre.
Methods
A retrospective case series of 23 patients with ITM between 2016-2021 at the Canberra Hospital. Patients with stage IV disease at diagnosis of ITM were excluded leaving 20 eligible patients. Patient demographics, primary and ITM clinicopathologic characteristics, treatment regimens and outcomes were analysed.
Results
Patients were predominantly male (70%), with mean age 61.8 years (SD=14.44). Primary melanomas were on lower limbs in 70% with mean Breslow thickness 2.96 mm (SD=1.82) and 31.25% were ulcerated. BRAF V600E mutation was present in five patients. Patients developed their first episode of ITM on average 28.99 months (SD=29.40) post diagnosis of their primary with 30% of patients presenting with innumerable ITM.
Treatment data was available for 19 of 20 eligible patients. Eighteen patients received immunotherapy as first-line management. Complete response (1 clinical, 10 PET-CT) to first-line therapy was observed in 11 patients (1 targeted, 10 immunotherapy). Immunotherapy was offered as second, third- and fourth-line treatment to four (n=6), three (n=4) and one (n=3) patient respectively. At least one grade three toxicity was experienced by 31.58% of patients comparable to other studies. Patients also underwent isolated limb infusion (3), radiotherapy (3), diphencyprone (2) and clinical trials (2).
Complete response was seen in 63.2% with complete response determined by PET-CT. In this group, there were two melanoma-related deaths occurring 24.53 and 14.07 months after initiation of systemic therapy.
Conclusions
Complete response was observed in 63% of patients confirming the utility of contemporary systemic therapy in ITM. Toxicity was similar to other published studies.