Impact of Tumor Pigmentation in 6934 Patients with Uveal Melanoma at a Single Center

Abstract

PurposeTo evaluate clinical features and outcomes associated with degree of tumor pigmentation in patients with uveal melanoma (UM) of the choroid and ciliary body. DesignRetrospective observational study. Subjects6,934 consecutive patients with choroidal or ciliary body melanoma between 1971 and 2007 from a single ocular oncology center. MethodsData on patient demographics, tumor characteristics, treatment approach, and clinical outcomes were collected. Comparisons between pigmented (>80% pigmentation by surface area), partially pigmented (20-80%), and non-pigmented tumors (<20%) were performed using relevant hypothesis testing. Survival analyses for metastasis and melanoma-related death were conducted using the Kaplan-Meier method with log-rank tests for univariate comparisons. A multivariate Cox regression analysis was performed to assess the independent effects of multiple covariates on time-to-metastasis. Main Outcome MeasuresExtraocular extension, ocular melanocytosis, time to tumor recurrence, tumor location, and melanoma-related metastasis and death. ResultsThere were 6,934 eyes with UM and the degree of tumor pigmentation was classified as pigmented (n=3,762; 54%), partially pigmented (n=2,115; 31%) or non-pigmented (n=1,057; 15%). Pigmented UM was associated with extraocular extension (p<0.001), ocular melanocytosis (p=0.003), earlier tumor recurrence (p<0.001), and more anterior tumor epicenter location (ciliary body, and equator to ora serrata) (p<0.001). Pigmented UMs also exhibited the highest 10-year metastasis rate at 26%, compared to 19% for partially pigmented UMs and 16% for non-pigmented UMs (p<0.001). Kaplan-Meier survival curves demonstrated differences among the tumor pigmentation groups for melanoma-related metastasis (p<0.001) and melanoma-related death (p<0.001). Multivariate Cox regression analysis for melanoma-related metastasis showed that pigmented UMs had a 29% higher relative risk of developing metastasis compared to partially pigmented UMs (p=0.002) and a 54% higher relative risk of developing metastasis compared to non-pigmented UMs (p<0.001). ConclusionPigmented choroidal and ciliary body melanoma is more often associated with ocular melanocytosis, extraocular extension, anterior tumor epicenter, and earlier tumor recurrence. We also revealed that patients with pigmented UMs demonstrate a higher 10-year rate of metastatic disease and have decreased metastatic survival relative to partially pigmented and non-pigmented UMs.