gms | German Medical Science

Background: Some children with the diagnosis of unilateral retinoblastoma later develop a retinoblastoma in the contralateral eye. It is important to recognize these metachronous tumors early to preserve eyes and vision with the adequate treatment and follow-up.

Methods: Clinical and genetic data of 417 children with initial diagnosis of a sporadic unilateral retinoblastoma and ophthalmological follow-up examinations until age 5 years were retrospectively analyzed to identify risk factors for the development of metachronous retinoblastoma.

Result: 21/417 children (5.0%) with unilateral retinoblastoma later developed a bilateral retinoblastoma. The tumor in the second eye was diagnosed at a median of age 1.6 years (range 0.32–16 years). In 20/21 children, the latent period from initial diagnosis to detection of the tumor in the second eye was <2.3 years. The genetic cause of tumor development was clarified in 246 children: 52 carried a RB1 mutation in blood DNA and 194 children showed two oncogenic mutations in tumor with normal RB1 alleles in blood DNA. All 14/246 (5.7%) children with metachronous bilateral retinoblastoma carried a heterozygous RB1 germline mutation. For children with germline mutation and unilateral retinoblastoma, the risk to develop metachronous retinoblastoma is inversely related to age at diagnosis.

Conclusion: The overall risk for children with germline RB1 mutation to develop a tumor in the other eye is estimated at 26.9% (14/52). Children without a mutation in blood DNA carry a very low risk for bilateral retinoblastoma (0/194). Early genetic analysis may identify those children at risk and guide treatment decisions and frequency of follow-up examinations.