External Beam Radiotherapy
Because retinoblastoma tumors are responsive to radiation, EBRT may be performed as a salvage technique; it is currently used only when chemotherapy has failed in the remaining eye. Two major concerns associated with EBRT have limited its use:
Germline mutations in RB1 are associated with a lifelong increased risk of subsequent independent primary malignancies (eg, osteosarcoma); this risk is exacerbated by exposure to EBRT, especially in children younger than 12 months.
EBRT involves risk of radiation-related sequelae, such as orbital hypoplasia, midface hypoplasia, radiation-induced cataract, and radiation optic neuropathy and retinopathy.
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.