Relative Importance of Quantifying Area and Vascular Patterns in Uveal Melanomas

Abstract

To test whether the cross-sectional area of choroidal and ciliary body melanomas and quantification of microcirculatory networks and parallel vessels with cross-linking are features associated with death from metastatic melanoma, and to compare new with conventional histologic prognostic features. The cross-sectional area of 234 ciliary body or choroidal melanomas was measured from digitized images of histologic sections. The percentage of cross-sectional area occupied by two microcirculatory patterns-networks and parallel vessels with cross-linking-was calculated for the 152 tumors containing at least one focus of either pattern. Kaplan-Meier survival curves were generated based on cross-sectional and percentage of cross-sectional areas of these patterns. Cox proportional hazard regression methods related time to death from melanoma with sets of predictor variables. For each model, percent variation explained was computed. Patient survival differs significantly when tumors are classified based on cross-sectional area: small (<16 mm2), medium (> or =16 mm2 but <61.4 mm2), and large (> or =61.4 mm2). Patients with tumors containing networks and parallel vessels with cross-linking microcirculation patterns that occupy 2% of cross-sectional area have a significantly worse prognosis than do those patients with tumors containing a smaller percentage of these patterns. Quantifying cross-sectional tumor area and the percentage area occupied by networks and parallel vessels with cross-linking microcirculatory patterns in ciliary body and cho. roidal melanomas provides significant prognostic information. Compared with more conventional prognostic characteristics, the most dramatic increase in prognostic information is provided by determination of the presence or absence of microvascular patterns.