| Purpose | to show that the most important risk factor of metachronous tumor development in the fellow eye in unilateral retinoblastoma, is an age at diagnosis of less than 12 months, while both the number of tumor foci at diagnosis and family history play only a marginal role, if any. |
| Methods | retrospective investigation on 167 unilateral retinoblastomas, diagnosed between 1980 and 2003. |
| Results | 11 out of 167 patients (6.5%) developed tumors in the fellow eye after diagnosis of unilateral retinoblastoma. 12 out of 167 (7.1%) had a positive family history for the disease, but only three of them later developed tumors in the fellow eye. Multiple foci were detected in 23 out of 140 patients (27 cases not evaluated), but only one patient with multiple foci at diagnosis, later developed tumors in the other eye. Finally all cases (11) who developed metachronous bilateral retinoblastoma, had had a diagnosis of unilateral retinoblastoma before the age of 12 months, while none of those who were diagnosed after that age, later developed metachronous bilateral tumors. |
| Conclusions | an age at diagnosis of less than 12 month seems to be the only relevant risk factor for metachronous tumor development in the fellow eye in unilateral retinoblastoma, but, strangely enough, a positive family history does not seem to influence this outcome |
|
