CHOROIDAL INVASION OF RETINOBLASTOMA - METASTATIC POTENTIAL AND CLINICAL RISK-FACTORS

There is considerable debate about the significance of choroidal invas ion of retinoblastoma with regard to metastatic disease. The charts of patients with retinoblastoma were reviewed over a 17 year period to d etermine the frequency of histopathological choroidal invasion of reti noblastoma and its risk for eventual metastatic disease. Sixty seven o f 289 eyes (23%) enucleated for retinoblastoma had histopathological e vidence of choroidal invasion. Those patients with choroidal invasion (with or without optic nerve invasion) were more likely to develop met astases than those without choroidal invasion (p=0.0001). When conside ring those patients with isolated choroidal invasion of retinoblastoma , excluding those with associated optic nerve invasion, there was no s ignificant risk but there was a trend towards the development of metas tases (p=0.10). The clinical factors found to be predictive for choroi dal invasion from retinoblastoma from a univariate analysis included i ncreased intraocular pressure (p=0.04) and iris neovascularisation (p= 0.007) and, from a multivariate analysis, iris neovascularisation (p=0 .02). The histopathological factors statistically associated with chor oidal invasion included the presence of optic nerve invasion (p=0.002) and poorly differentiated retinoblastoma (p=0.003). Factors not predi ctive for choroidal invasion included the age, race, and sex of the pa tient and the tumour laterality, inheritance, size, and growth pattern . Choroidal invasion of retinoblastoma is a risk for metastases, espec ially if it is associated with any degree of optic nerve invasion.