Brain MRI Screening for Bilateral Retinoblastoma Patients

Trilateral retinoblastoma (TRB), intracranial neoplasm in heritable retinoblastoma patients, is a very rare fatal disease. Many ocular oncology centers conduct routine screening of retinoblastoma patients by brain imaging. Nevertheless, there is a debate regarding its ability to prolong TRB patients' survival and the number-needed-to-treat. We recommend baseline screening brain imaging in bilateral retinoblastoma patients, followed by imaging according to clinical need. We aim to see if this screening schedule has an impact on patients' survival.

In a retrospective observational study, we reviewed the medical records of patients diagnosed with bilateral retinoblastoma at a tertiary medical center ocular oncology unit between 1.7.1986 and 1.2.2020, who had at least 36 months follow-up or retinoblastoma-related death. We collected data on patients' demographics, clinical features, systemic evaluation, treatment, follow-up, and outcome.

The analysis included 109 patients, 60 males and 49 females, diagnosed with bilateral retinoblastoma at a median age of 7.0 months (range 0.43-70.5 months). Germline mutation was found in 43 patients (39.4%) and somatic mutation in 15 patients (13.8%). Genetic status was not recorded in 51 patients (46.8%). Fifty-eight patients (53.0%) underwent baseline brain imaging (MRI in 42 patients and CT scan in 16 patients), in all of whom it was within normal limits. During a median follow-up of 138 months (range 19-787 months), 35 children had follow-up brain imaging (MRI in 25 patients and CT in 10 patients). One patient developed symptomatic TRB during follow-up, and is alive and disease-free (0.9%, Cl:0.02%-5.6%). Looking at survival, six patients (5.5%) developed metastatic disease, and eight patients (7.3%) expired, in all of whom death was retinoblastoma-related.

Due to TRB rarity, routine screening by baseline brain MRI may be sufficient, avoiding anesthesia, expenses, distress, and unnecessary interventions, without a significant impact on patients' survival. Nevertheless, due to TRB fatality and treatment morbidity, periodic brain MRI until age 3 is a legitimate option.