No differences in the long-term prognosis of iris and choroidal melanomas when adjusting for tumor thickness and diameter

Abstract

Objective To assess the long-term prognosis for patients with iris melanomas and compare it with the prognosis for small choroidal melanomas. Design Retrospective observational case series. Methods All patients treated for iris melanomas at a single referral institution between January 1st 1986 and January 1st 2016 were included. Patients treated for small choroidal melanomas during the same period were included for comparison. The cumulative incidence of melanoma-related mortality was calculated. Patient and tumor characteristics and size-adjusted hazard ratio (HR) for melanoma-related mortality were compared between iris and small choroidal melanomas. Results Forty-five iris melanomas and 268 small choroidal melanomas were included. Twenty-four iris melanomas (53%) had been treated with local resection, 12 (27%) with Ruthenium-106 brachytherapy, 7 (16%) with enucleation and 2 (4%) with proton beam irradiation. Twenty-one (68%), 7 (16%) and 2 (4%) of the iris melanomas were of the spindle, mixed and epithelioid cell types, respectively. Twenty-three patients had deceased before the end of follow-up. Median follow-up for the 22 survivors was 13.3 years (SD 9.4). Patients with iris melanomas were more often asymptomatic at presentation and had a trend towards significantly lower age (59 versus 63 years, Student’s T-tests p = 0.057). Further, iris melanomas had significantly smaller basal diameter (5.8 versus 8.0 mm, p < 0.0001) and tumor volume (79 mm3 versus 93 mm mm3, p < 0.0001) but greater thickness (3.0 versus 2.5 mm, p < 0.0001). The cumulative incidence of iris melanoma-related mortality was 5% at 5 years after diagnosis, and 8% at 10, 15 and 20 years. The incidence was not significantly different to small choroidal melanomas (Wilcoxon p = 0.46). In multivariate Cox regression with tumor diameter and thickness as covariates, patients with choroidal melanomas did not have increased HR for melanoma-related mortality (HR 2.2, 95% CI 0.5–9.6, p = 0.29). Similarly, there were no significant survival differences in matched subgroups (Wilcoxon p = 0.82). Conclusions There are no survival differences between iris and choroidal melanomas when adjusting for tumor size. The reason for the relatively favorable prognosis of iris melanomas compared to melanomas of the choroid and ciliary body is likely that they are diagnosed at a smaller size.

Trends in Uveal Melanoma Presentation and Survival During Five Decades: A Nationwide Survey of 3898 Swedish Patients

“…The recent observation of a 80–90% metastatic rate among patients with untreated primary tumors indicates that a beneficial effect might exist after all ( 9 ). This may be further corroborated by the observation that there are no survival differences between melanomas originating in the choroid or the iris when adjusting for tumor size, although additional studies are needed to verify this observation ( 34 ). The reason for the relatively good prognosis in iris melanoma is likely that they are typically diagnosed at a small size.…”

A prognostic classification system for uveal melanoma based on a combination of patient age and sex, the American Joint Committee on Cancer and the Cancer Genome Atlas models

“…We have previously shown that patients presenting with a shadow in the visual field have significantly shorter disease‐specific survival, regardless of other symptoms, tumour size, location, local extent and stage (Fili et al, 2020 ). In turn, tumours from UM patients that report a visual field shadow are more likely to display vasculogenic mimicry and greater density of PAS positive patterns, which may underpin the association between this symptom and poor prognosis (Sabazade et al, 2021a , 2021b ).…”

“…One exception is a large study by Kujala et al ( 2013 ), who found that tumour diameter, tumour thickness, CBI and extraocular extension were all independent predictors of melanoma‐related mortality in multivariate Cox regression (Kujala et al, 2013 ). In contrast to iris melanomas who have no better prognosis than choroidal melanomas when adjusting for tumour diameter and thickness, this should make it unlikely that increased tumour size is the real reason for the prognostic implication of CBI (Johansson et al, 2020 ; Sabazade et al, 2021a , 2021b ). The American Joint Committee on Cancer (AJCC) classification of UM consequently assigns tumours with CBI a subcategory with shorter metastasis‐free survival (Kujala et al, 2013 ; Kujala & Kivela, 2005 ; Simpson et al, 2015 ).…”

When Is the Optimum Radiological Response to Proton Beam Therapy in Uveal Melanoma?

“…The 15-year melanoma-specific survival in Scotland is 83.8%, 81.3%, and 100% for choroidal, ciliary body, and iris melanomas, respectively [3]. Fifteen-year survival for in Sweden for choroidal and iris melanomas has been reported as 84% and 92%, respectively [4], and 5- and 10-year melanoma-specific survival figures for choroidal melanoma in the USA have been reported as 87% and 78.5% [5], respectively.…”