Outcome of children with retinoblastoma and isolated choroidal invasion.

Objectives: To evaluate the outcome of children with different degrees of choroidal invasion, to compare different systems for grading the extent of choroidal invasion, and to assess the role of concomitant prelaminar optic nerve and anterior segment invasion as predictors of extraocular relapse.

Design: Retrospective analysis of children included in 4 prospective protocols (January 1, 1989, through June 31, 2010). Children with postlaminar optic nerve or scleral involvement and overt extraocular disease were excluded. Adjuvant chemotherapy was not scheduled. All slides were reviewed, and massive involvement was classified according to 3 definitions: (1) extending at least 3 mm in any dimension, (2) through the choroid's whole thickness, and (3) more than 50% of the thickness and/or more than 1 cluster.

Results: One hundred sixty-seven children (35 with massive invasion) were studied (136 did not receive adjuvant therapy). The probability of 5-year event-free survival was 98.1% and the probability of overall survival was 98.7% because 1 patient relapsed. Children with massive invasion had a significantly lower event-free survival probability (94.2%) compared with those with focal invasion (99.2%) (P = .04). However, no significant difference was found in overall survival probability (98.7% vs 99.2%; P = .29). No significant effect of other risk factors was found.

Conclusions: Survival was excellent without adjuvant therapy, and no other factors correlated with survival. Children with massive invasion have a higher relapse rate but comparable survival to those with focal invasion provided that aggressive therapy for extraocular relapse is available with adequate safety conditions.