Prognostic factors in malignant melanoma of the choroid: a retrospective survey of cases occurring in Northern Ireland between 1965 and 1980.

In Northern Ireland between 1965 and February 1980 one hundred eyes were enucleated following diagnosis of malignant melanoma of the choroid. The pathology of 87 cases was available for re-examination. Data on those patients still alive were examined together with the post-mortem reports of those deceased. A mathematical model was constructed to assess tumour volume more accurately. Survival was analysed using univariate and multivariate methods. Actuarial survival curves were constructed and two multivariate regression models were used--the proportional hazards model and the log-logistic model. In addition person years at risk analysis was used to compare survival with the Northern Ireland population. When the data were examined univariately, the location of the tumour, cell type, degree of invasion and the parameters of size (height, diameter and volume) were all significant prognostic indicators. When multivariate analysis was employed, the degree of invasion did not contribute significantly to the model, this being accommodated by tumour size. Cell type was also shown to be of less importance in the multivariate models. The various prognostic indicators together with the person years at risk analysis are discussed.