Intensive surveillance and aggressive multi-modal treatment for liver metastases from uveal melanoma.

Abstract

9549 Background: We report utility of diagnostic laparoscopy and long-term survival outcome for patients undergoing multi-modal treatment for liver metastasis from uveal melanoma (LMUM). Methods: All consecutive patients with suspected oligo-metastatic LMUM diagnosed on screening ultrasound were discussed at Hepato-Pancreatico-Biliary (HPB) Tumour Boards (Jan2010-Nov2024) and were offered multiple lines of surgical / ablation, liver directed and systemic therapies as appropriate, with data censored on 30th November 2024. Liver specific overall survival was calculated from date of index liver resection to date of last follow-up (censored) or death. Results: Out of the 58 patients LMUM, 13 (22%) patients had multifocal disease or other concurrent cancer diagnosed on further imaging assessments (dedicated MRI liver and FDG-PET scan). Of the remaining 45 patients assessed with diagnostic laparoscopy a further 15 (33%) had multifocal hepatic metastasis. Thus 27 patients (46%) had multifocal disease precluding liver resection / ablation (Group A). 21 of 58 patients with LMUM had liver resection as a primary modality with majority (18/21) achieving a R0 resection margin and a further 10 had liver ablation (Group B). Both groups received additional lines of treatment. Patients with oligo-metastatic disease undergoing liver resection / ablation as primary modality of treatment (Group B) had longer overall survival (median liver-specific OS = 45.1 (95% CI: 31 – not reached) months; p<0.0001, log-rank (Mantel-Cox) test, Hazard ratio (HR): 7.86, 95%CI: 3.52-17.5) after treatment of metastatic disease compared to multi-focal disease treated with immunotherapy as primary modality (Group A, median 18.6 (95% CI: 13-26) months). Whilst the age of diagnosis of LMUM was similar for both Groups A (multifocal metastasis, median 68 years) and B (oligometastatic disease, median 63 years) (two-tailed Mann Whitney U test, p=0.12), patients group B were younger at time of diagnosis of primary UM (median 57 (B) versus median 66 years (A), two tailed Mann Whitney U test, p=0.03) with a longer interval to metastatic progression (median 1325 days (B) versus median 704 days (A), two tailed Mann Whitney U test, p=0.006). Conclusions: This largest series of patients with LMUM from the United Kingdom emphasises the vital role of diagnostic laparoscopy to rule out bi-lobar miliary disease. We report impactful overall survival with multimodal treatment for LMUM and highlight prognostic features for further validation.