Retinoblastoma is the most common malignant tumor of the eye in children. It has been known and studied for many years resulting in treatments so effective that more than 95% of patients have at least a 5 year survival rate.
This is almost entirely a disease of infants and very young children. The vast majority of cases are diagnosed before the age of 3 years, although rarely they may not be found until after 5 years of age. The most common presenting sign is a white reflex noted in the pupil of one eye. Another presenting sign is a crossing of the eyes but there are numerous other disorders that can cause this. Because this is a malignant tumor, early diagnosis and treatment are important.
The majority of new cases occur sporadically, i.e., without a family history. However, about one-third inherit the responsible mutation from a parent in which case these children can pass on their susceptibility to their children.
Individuals with retinoblastoma have mutations in both copies of a tumor suppressor gene that normally controls the replication of cells. Lacking this suppression, the retinal cells divide unchecked, producing the mass of cells constituting the tumor and enabling the cancerous tissue to continue to grow inside the eye and even spread outside.
Calculating the risks of passing on the susceptibility of this tumor is complex because of the fact that not all retinoblastoma cases are heritable. That is, many patients develop the tumor through the unfortunate occurrence of having mutations occur in the two genes after birth. Since the mutations usually occur only in the immature cells of the retina (these usually mature and lose their susceptibility at about the age of 2.5 years) so passing on the mutation does not occur. However, a minority of individuals with retinoblastoma have inherited one mutation from their parent since they carried it in their reproductive cells. Such children then have the unfortunate experience of acquiring another mutation in the second suppressor gene after birth. Since every cell in their bodies has the single mutation, they can pass this susceptibility to each if their children with an about 50% chance. Inheriting a disabled suppressor gene means that all cells of the body are now at risk of acquiring a mutation in the second suppressor gene and hence have the chance of developing other tumors as well and this remains throughout life.
Because retinoblastoma is curable, early diagnosis and proper treatment is vital. Every child with a parent who had this tumor should have a complete medical eye examination at birth and repeatedly throughout the first decade of life. Thorough pediatric examinations are also important because of the risk of other tumors. Only your eye doctor can diagnose this tumor and the prognosis is excellent with good treatment. Treatment protocols vary widely and your eye doctor can work with other specialists to design the most appropriate procedures.