Prognostic implications of monosomy 3 in uveal melanoma

Background A high proportion of patients with uveal melanoma die of metastatic disease. In a subgroup of uveal melanomas there is the loss of one chromosome 3. To assess the prognostic implications of this genetic anomaly, we studied 54 patients for a median of 3·4 years. Methods 180 patients underwent primary enucleation for malignant uveal melanoma at the Ophthalmology Department of the Universitätsklinikum Essen between 1987 and 1993. Tumour material was available for chromosome analysis and DNA preparation from 69 of these patients (for logistic reasons unlikely, we believe, to introduce bias). 15 patients were excluded from our study: nine because the methods for assessment of monosomy 3 were unsuccessful; five because of insufficient information about their relapse status; one because histopathological data were incomplete. Of the 54 remaining patients, the tumours of 16 were assessed for copy number of chromosome 3 by karyotype analysis, of 30 by comparative genomic hybridisation, and of eight by both techniques. Clinical status was assessed by contact with family doctor or a clinical check up. Statistical analysis was by the logrank test and Cox proportional-hazard regression. Findings The tumours of 30 patients had monosomy 3. 17 (57%) of these patients relapsed with metastatic disease, and the 3-year relapse-free survival rate was 50%. By contrast, of the 24 patients whose tumours had retained both chromosomes 3, none developed metastatic disease. In univariate analysis monosomy 3 was the most significant (p<0·0001) predictor of poor prognosis in uveal melanoma, followed by tumour location (p<0·0007) and tumour diameter (p<0·0021). Histopathological subtype, age, sex, extrascleral growth, and tumour thickness had no additional predictive value. Interpretation In uveal melanoma, monosomy 3 is a significant predictor of both relapse-free and overall survival.