Retinoblastoma

Retinal cancer of early childhood

Overview

Retinoblastoma is a malignant tumor of the retina that develops in early childhood, usually before the age of five, and it is the most common primary eye cancer in children. It arises from mutations in both copies of the RB1 tumor suppressor gene. In the heritable form, one mutation is present in all cells from birth, often causing tumors in both eyes and an increased lifelong risk of other cancers such as sarcomas, while in the non heritable form both mutations occur within a single retinal cell. The study of its inheritance led Alfred Knudson to propose the two hit hypothesis in 1971, and RB1 was the first tumor suppressor gene to be cloned. The classic sign is leukocoria, a white pupillary reflex often noticed in photographs, and strabismus is another common presentation. Treatment depends on the extent of disease and includes intravenous or intra arterial chemotherapy, laser and cryotherapy, plaque radiotherapy, and enucleation. Survival is very high where it is diagnosed early, but much lower in regions where diagnosis is often late.