Microvessel count predicts survival in uveal melanoma

Purpose. Microvessel density has become established as an important prognostic indicator for many tumour types. This study investigates the microvessel density as a prognostic factor for survival in patients with uveal melanoma. Methods. Factor VIII related antigen was identified immunohistochemically in bleached sections from 123 tumours. Maximum blood vessel density in an area of 0.25mm2 was recorded along with other accepted prognostic information. Results. Microvessel density was the single most important prognostic factor. The actuarial 5 year survival for patients divided into quarters on the basis of counts was 42% for the top quarter, 55% for the next, 70% for the next and 90% for the lowest quarter. On univariate testing, cell type, tumour size, presence of extra-ocular extension, ciliary body involvement, mitotic count and five of the Folberg patterns were significant. In a forward selection Cox's proportional hazard model, microvessel density was the most important variable and the only other variable to enter the model was tumour size. Conclusions. Microvessel density is an important prognostic factor for survival in patients with uveal melanoma and is the best single measure of tumour grade.