A modern view of the phenomenon of trilateral retinoblastoma from the positions of ophthalmic oncology and neurooncology. Part I. Literature review

Trilateral retinoblastoma (TRb) phenomenon is a combination of bilateral retinoblastoma (Rb) (in most cases) and molecular group A pineoblastoma (Pb). The study of this phenomenon has been going on for more than 30 years, is interdisciplinary in nature and includes two conceptual points of view from the positions of ophthalmic oncology and neurooncology. The frequency of this phenomenon detection varies from 0.75 to 2 % in the entire research group and from 2.1 to 3.5 % in the structure of bilateral forms. Intraocular lesions were presented by a bilateral variant in 91.5 % of clinical cases. Intracranial tumor in the pineal gland projection was detected in 73.3 % of cases, suprasellar localization – in 20 %. The ratio of synchronous and metachronous disease variants is heterogeneous and multidirectional and varies from 1,3:1 (according to large retrospective and prospective studies of Y. Zhang, X. Fang, T. Gui, S. Qureshi et al.) to 1:2,1–1:4 (according to meta-analysis of M.C. DeJong, R. Yamanaka et al.). All TRb cases were detected before the age of 60 months; the synchronous variant was detected before the age of 36 months in most clinical cases. Morphological and molecular biological study of the tumor substrate in children with TRb is currently disjointed in relation to the intraocular and intracranial segments of this phenomenon, Rb and Pb respectively. The most significant characteristics presented by determination of the germline RB1 gene mutation in blood samples, assessment of RB1, TFF1 proteins expression, a variant of the mutational event in the RB1 gene, the presence of N-MYC gene amplification, 1q gain, 16q loss in the tumor substrate of intraocular and/or pineal/suprasellar localization. In the treatment of children with the TRb phenomenon, both complex protocols and individual therapy programs are used. The optimal therapeutic strategy is unknown.