Immunoembolization in liver-predominant metastatic uveal melanoma: a single-center retrospective analysis.

Introduction: Approximately 50% of patients with uveal melanoma develop metastatic disease, most commonly involving the liver, and prognosis remains poor. Immunoembolization (IE) is an established liver-directed therapy for patients with liver-dominant metastatic uveal melanoma (mUM), though comparative data with other regional therapies remain limited. We present a single-center retrospective analysis of IE in hepatic mUM and compare outcomes with those reported in the Phase 3 FOCUS trial evaluating melphalan via percutaneous hepatic perfusion. Methods: All patients with liver-dominant mUM treated with IE between 2010 and 2023 at our institution were included. Clinical records were reviewed for demographics, tumor characteristics, treatment details, and outcomes. The primary endpoint was disease control rate (DCR), defined as complete response (CR), partial response (PR), or stable disease (SD). Secondary endpoints included progression-free survival (PFS) and overall survival (OS), with subgroup analyses based on prior systemic therapy exposure. Descriptive statistics were used for analysis. Results: Forty-three patients (62.8% female; median age 62 years; all Caucasian) underwent 249 IE procedures (mean 5.8 procedures per patient) over a median treatment duration of 9.1 months. Choroidal primaries accounted for 95.3% of cases, and 90.7% had liver-only metastases. The overall DCR was 27.9% (CR 4.7%, PR 20.9%, SD 2.3%), while 62.8% experienced disease progression. Median PFS was 0.85 months, and median OS was 32.7 months. One- and two-year OS rates were 69.8% and 55.8%, respectively. In subgroup analysis, patients who had received prior systemic therapy (n=12) demonstrated improved outcomes compared with treatment-naïve patients, with longer median PFS (29.9 vs. 7.2 months) and higher 2-year OS (60.0% vs. 47.0%). Compared with outcomes reported in the FOCUS trial, IE demonstrated shorter median PFS (0.85 vs. 9.0 months) and lower DCR (27.9% vs. 73.6%), but longer median OS (32.7 vs. 20.5 months). Discussion: IE produced overall survival outcomes comparable to hepatic melphalan delivery despite lower radiographic response rates. Notably, patients previously treated with systemic therapy experienced improved outcomes, suggesting a potential sequencing effect. These findings support IE as a viable liver-directed therapy for liver-dominant mUM. Prospective, multicenter trials are warranted to clarify optimal sequencing strategies and enhance therapeutic outcomes.