Uveal melanomas presenting in the anterior segment of the eye: Anatomical localization and survival rate

Abstract

Purpose : Uveal melanomas are classified according to origin and the prognosis varies significantly between the different types. In cases with several uveal structures involved, classifying the melanoma can be problematic. This is especially the case for melanomas located anteriorly in the eye. Additionally, tumor staging for iris melanomas (AJCC8th edition) can be difficult to obtain without a histological assessment.
We set out to compare survival on uveal melanomas presenting in the anterior chamber based on anatomical extension of the tumors.

Methods : A nationwide retrospective cohort study of uveal melanomas presenting in the anterior chamber from 1943 to 2022. Data were obtained from clinical and pathology records, the Danish Cancer Register and the Danish Cause of Death Register.
Tumors were divided into four groups; 1) melanomas restricted to iris, 2) melanomas involving iris and ciliary body, 3) complete or partial ring melanomas and 4) melanomas involving iris, ciliary body and choroid.
The cox proportional hazard model, overall- and disease specific survival Kaplan-Meier curves were used to compare survival between the four groups.

Results : The population consisted of 823 patients. A histological diagnosis was obtained in 801 cases. Cause of death was known for 439 of 497 diseased patients.
Patients were distributed as follows; group 1) 318, group 2) 159, group 3) 72 and group 4) 274.
Kaplan Meier survival statistics for overall survival and disease specific survival differed significantly (p < 10^-4) between the groups with survival probability decreasing from group 1 to group 4 (fig. 1+2).
The cox proportional hazard model for overall survival showed hazard ratios of: group 2:4; HR=1.5, HR=2.9, HR=6.5 ref: pure Iris melanoma and for disease specific survival group 2:4; HR=26, HR=100, HR=327 ref: pure Iris melanoma

Conclusions : We found significant differences in survival when melanomas were divided into different groups according to anatomical extension. We propose to evaluate the current AJCC classification accordingly, since the present classification is difficult to administer in a clinical setting, and only few patients are classified as T3 and T4 in the present classification of iris melanomas ¹.


1: Shields CL. et al., “Iris Melanoma Outcomes Based on the American Joint Committee on Cancer Classification (Eighth Edition) in 432 Patients”. Ophthalmology 2018;125:913-923

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.