MRI in the detection of hepatic metastases from high-risk uveal melanoma: a prospective study in 188 patients

Background/aims To evaluate MRI in the detection of asymptomatic hepatic metastases from uveal melanoma. Methods A single-arm prospective cohort study. Participants We enrolled 188 patients whose predicted 5-year mortality from uveal melanoma exceeded 50%. This prognostication was performed by multivariate analysis of clinical stage, histological grade and genetic type, using our online tool, based on Accelerated Failure Time modelling. These high-risk patients underwent a six-monthly assessment, which included history-taking, clinical examination, hepatic MRI (without contrast, unless suspicious lesions were identified) and biochemical liver function tests. Results Ninety (48%) of the 188 patients developed detectable metastases, a median of 18 months after ocular treatment. Six-monthly MRI-detected metastases before symptoms in 83 (92%) of 90 patients developing systemic disease, with 49% of these having less than five hepatic lesions all measuring less than 2 cm in diameter. Of these 90 patients, 12 (14%) underwent hepatic resection, all surviving for at least a year afterwards. Conclusions Six-monthly MRI detects metastases from high-risk uveal melanoma before the onset of symptoms, enhancing any opportunities for early treatment of metastatic disease and clinical trial participation. Whether these actually result in prolongation of life, after taking lead-time bias into account, requires further investigation.