ABSTRACT

The PhD dissertation studies epidemiological and clinical aspects of ocular malignant melanoma.

The study was carried out in co-operation with the Department of Experimental Clinical Oncology and Department of Ophthalmology, Århus University Hospital (ÅUH) and the Centre for Cancer Documentation, Department of Prevention and Documentation, Danish Cancer Society.

The purpose was to study the incidence, relative survival, prognostic factors for survival, and a potential change in the nature of the disease during the last approximately 50 years in Denmark, and to study the visual outcome after radiation brachytherapy since 1988.

The age-standardised incidence rate in Denmark during the period 1943-1997 was 0.7 per 100,000 person-years (n=2573). No time trend was found in contrast to a tenfold increase in the incidence rate of cutaneous melanoma during the same period, linked to increased exposure to solar ultraviolet light. This finding does not support causality between ultraviolet light and ocular melanoma. The relative survival of patients diagnosed in Denmark during the period 1943-1997 and followed through 2002 was stable for men, however, the relative survival improved for women with no obvious explanation and might be a chance finding. In a consecutive series of 293 patients from the Dept. of Ophthalmology, ÅUH/Århus County treated by enucleation for a choroidal or ciliary body melanoma during the period 1955-2000, the risk for melanoma death was high for patients with tumours of large basal diameter, anterior location and non-spindle cell type. Additional risk factors for death from all causes were male sex and high age.

Today, cutaneous melanomas are diagnosed at an earlier stage, which has improved survival. In an unselected cohort of 209 patients diagnosed with a choroidal or ciliary body melanoma during the period 1955-2000 in Aarhus County, no time trend was found for tumour size or other clinical and histopathological characteristics. Thus, the presentation of the disease at diagnosis seems to have remained unchanged over time.

Fifty-five consecutive patients underwent during the period 1988-2000 radiation brachytherapy for a choroidal melanoma at the Dept. of Ophthalmology, ÅUH. A clinically significant visual acuity loss, local recurrence in one third and eye preservation in two thirds was found after five years.

In conclusion, the epidemiology and clinical aspects of ocular malignant melanoma have largely remained unchanged during the last half century. This is in contrast to the literature on cutaneous melanoma, which has shown a steep increase in the incidence rate, smaller tumours at diagnosis, and improved survival from earlier diagnosis.