Epidemiological characteristics of retinoblastoma in children attending the Mexican Social Security Institute in Mexico City, 1990-94.

The object of this study is to present descriptive epidemiological characteristics of retinoblastoma (Rb) in children aged 0-14 years, seen at the Mexican Social Security Institute hospitals in Mexico City (MC) from 1990 to 1994. This is a retrospective, observational hospital survey. Clinical records of 52 Rb cases were reviewed; 39 were patients who did not reside in MC (non-residents), and 13 were MC residents. The study period was 1990-94. The male/female ratio (M/F) was 1.6. Average annual incidence (AAI) was estimated by age and sex (rates per 1000000). Annual average percentage change (AAPC) in incidence rates was estimated in children from 0 to 14 years. The AAI for MC residents was 3.2; the highest rate being for those <1 year olds (rate of 20.8); AAPC was 6.9% [95% CI -27.5, 57.4]; the highest incidence was for the south-eastern region of MC residents (rate of 5.9); 13 cases (25%) were diagnosed at stage III or IV, and 11 cases (21.2%) were bilateral. Incidence of Rb is similar to that in developed countries and shows no increasing trend. Patients from communities outside MC are more frequently diagnosed at stages III and IV.