Orbital development in long-term survivors of retinoblastoma.

Abstract

PURPOSE To determine the effects of enucleation, irradiation, and age at diagnosis on bony orbital growth in long-term survivors of retinoblastoma using measurements based on computed tomographic (CT) imaging. PATIENTS AND METHODS We used CT obtained at a median age of 13 years to measure orbital volume and configuration in 54 patients who had been treated for retinoblastoma a minimum of 5 years previously. RESULTS Enucleation and high-dose orbital irradiation (> 35 Gy) both independently adversely affected orbital development (P = .014 and P = .022, respectively). Orbital volume differences for children treated when < or = 1 year old were no greater than those for children treated when older than 1 year of age. In children treated for bilateral retinoblastoma, the impact of enucleation on orbital development was not statistically different from that of irradiation (P = .13). Small implants (12 to 14 mm in diameter) were more commonly associated with smaller orbital volumes. Migration of orbital implants was associated with the smaller orbital sphere size in children < or = 1 year of age (P < .035). CONCLUSION Treatment for retinoblastoma compromises orbital development. Resulting orbital asymmetry seems to be at least partially related to the size of the implant. Detailed imaging-based measurements of orbital volume and configuration may aid the planning for cosmetic and reconstructive surgery in those who develop orbital asymmetry.