Ocular Tumours

Cuban study may provide template for other resource-limited settings. Dermot McGrath reports from the EURETINA 2021 Virtual Meeting

Alarge-scale epidemiological study of retinoblastoma in Cuba suggests that high survival rates can be achieved despite limited resources in treatment, a new study concludes.

“The incidence rate of retinoblastoma in Cuba has been stable over the past nine years, with Cuban retinoblastoma patients achieving five-year survival estimates similar to the United States, despite limited resources,” Liudmira González Rodriguez MD said.

She added, however, that lower ocular survival is related to the high number of unilateral and advanced retinoblastoma cases and the limited resources of treatment.

“Future studies are necessary to determine whether the Cuban model can be replicated to improve retinoblastoma outcomes in other similar resource-limited settings,” she said.

Early diagnosis of retinoblastoma, the most common intraocular cancer, can save both a child’s life and vision, Dr González Rodriguez noted. However, patients from lower-income settings often present with late disease, many with extraocular extension and some already with metastasis, and their prognosis is poorer than patients living in higher-income settings.

“About 80% to 90% of children with retinoblastoma live in developing countries, and there is a disparity in overall and ocular survival between higher and lower income countries. However, the epidemiology of retinoblastoma is not well understood nor clearly reported in Cuba, which was one of our main motivations for conducting this study. Furthermore, because Cuba represents a well-defined and enumerated population, it is a unique setting in which to study the epidemiology of this disease,” she said.

The retrospective study included 76 patients in Cuba diagnosed with retinoblastoma between 2010 and 2018. The fiveyear overall survival rates were calculated for cases diagnosed during the 2010 to 2012 period. The mean age at diagnosis was 1.2 years (range 0.6 to 2.3 years), 40 were males (52%), and 48 patients (62.3%) were unilateral cases.

Of the 106 eyes included in the study, 38 (36%) had exophytic tumour type and 76 (70%) had class D tumours or higher according to the Intraocular Classification of Retinoblastoma (ICRB). The ICRB divides intraocular retinoblastomas into five groups, A (lowest risk) through E, based on the extent of the cancer and the chances of saving the eye using current treatment options.

Leukocoria was the chief complaint in 53 patients (50%) and strabismus in 22 (21%). A total of 78 eyes (74%) were enucleated. The incidence rate was 1.39 cases per 20,000 live births over the study period.

“The overlapping confidence intervals show the retinoblastoma incidence rates did not differ by year during the study period, which is in line with the theory there are no clear demographic or environmental risk factors associated with retinoblastoma, thereby explaining the stable worldwide incidence rates,” Dr González Rodriguez said.

The overall survival in retinoblastoma cases over a five-year period was 94.6%, compared to the estimated figure of 95.2% for the United States based on the scientific literature, she said.

Liudmira González Rodriguez MD is an ophthalmologist at the Cuban Institute of Ophthalmology in Havana, Cuba. liudmilagr@infomed.sld.cu

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