Among a cohort of Asian patients with uveal melanoma, their largest tumor basal diameter is most strongly associated with risk for metastasis and metastasis-related death, according to research results published in Ophthalmology Retina. 

While the prevalence and association of congenital oculocutaneous melanosis in White populations with uveal melanoma is known, the literature is lacking regarding data on uveal melanoma prevalence in Asian populations. Therefore, researchers conducted a retrospective cohort study of 1151 patients with a clinical uveal melanoma diagnosis treated at the Beijing Tongren Eye Center between June 2005 and July 2020. Patients were divided into 1 of 3 groups based on the type of primary therapy received: iodine-125 brachytherapy, local resection, or enucleation (n=929, 57, and 165, respectively). 

Median follow-up duration was 24 months (range, 8-24 months). At baseline, mean tumor basal diameter was 12.2 mm, and mean tumor thickness was 7.0 mm. Mean age at uveal melanoma presentation in patients with congenital oculocutaneous melanosis was 48.2 years, compared with 46.8 years in patients with no congenital oculocutaneous melanosis. 


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Results of a Kaplan-Meier analysis estimated the metastasis rate and metastasis-related death rates at multiple intervals over a 10-year period. In patients with uveal melanoma, estimated 1-, 3-, 5-, 7-, and 10-year metastasis rates were 2.4%, 9.5%, 15.5%, 21.4%, and 24.5%, respectively; estimated metastasis-related death rates were 0.7%, 4.3%, 7.5%, 11.9%, and 11.9%, respectively, at the same time points. 

Results of a univariable Cox proportional hazard regression analysis indicated that largest basal tumor diameter, ciliary body involvement, and tumor thickness were all factors that increased risks for metastasis and metastasis-related death. Results of a multivariable analysis found that only largest tumor basal diameter was related to increases in these risks. 

In a nested case-control study, researchers matched 56 people with uveal melanoma but without congenital oculocutaneous melanosis to 23 patients with uveal melanoma and congenital oculocutaneous melanosis. Patients were matched by age, tumor thickness, tumor basal diameter, and ciliary body involvement. Median follow-up duration was 53 months (range, 33 months to 67 months). Results of a log-rank test indicated that prognosis between these groups was similar, suggesting that congenital oculocutaneous melanosis did not increase uveal melanoma metastasis risk. 

Study limitations include those inherent to retrospective research, the use of a single center and the associated possibility for selection bias, a systematic underestimation of actual metastasis and metastasis-related death risk, and an underpowered nested case-control study. 

“To our knowledge, this is the largest [uveal melanoma] cohort in the Asian population,” the research concludes. “We confirmed again that there were clinical characteristics discrepancies that existed between…Asian and Caucasian [uveal melanoma] patients. …[T]he largest tumor basal diameter, rather than tumor thickness, ciliary body involvement, or subretinal fluid, was associated with metastasis and metastasis-related death.”

Future studies should include a genetic analysis of congenital oculocutaneous melanosis in order to reveal its relationship with uveal melanoma. 

Reference

Zhou N, Zhang R, Liu Y, Wei W. Clinical characteristics of uveal melanoma and association of metastasis of uveal melanoma with congenital oculocutaneous melanosis in Asian patients analysis of 1151 consecutive eyes. Ophthalmol Retina. Published online January 11, 2021.  doi:10.1016/j.oret.2021.01.001