A New Era of Organ-Preserving Treatment in Pediatric Intraocular Retinoblastoma in Russia: A Multicenter Cohort Study

Background.Retinoblastoma (RB) is a life threatening cancer disease. A breakthrough in the treatment of children with RB is associated with the improvement of conservative treatment that was administered in at least one of the two tumor-affected eyes in most bilateral cases, that was chemotherapy both systemic and local (selective intra-arterial and intravitreal) in most cases combined with laser therapy, cryotherapy, or brachytherapy. The development of such techniques as local chemotherapy is focused on preservation of visual functions, reducing the number of enucleations and radiotherapy (RT) course. The success of the healing of RB is closely associated with a multidisciplinary approach to diagnosis and treatment, as well as specialized longterm follow-up clinical examination.Objective.eye and vision preservation against large intraocular tumors with different growth types and localization without the course of remote radiation therapy was the main purpose.Methods.In the period from September 2012 to January 2016, the study enrolled 45 patients with RB when at least one eye had intraocular tumor spread corresponding to the group C or D. According to the ABC international classification, patients have a relatively good prognosis for organ-preserving treatment. 4 of 18 children with bilateral RB had undergone primary enucleation of worse eye the worst eye, group E; 49 (77.8%) of the 63 affected eyes had features for groups C and D. In this study, no patient received local chemotherapy initially, only after prior systemic chemotherapy. Selective intra-arterial chemotherapy (SIAC) was applied to 41 patients (45 eyes; mean course number was 2), and 32 patients (34 eyes) had undergone intravitreal chemo therapy (IViC) (mean course number was 2). Focal therapy and local chemotherapy were the main methods of treatment for progression (new lesions on the retina) in 8 (16.3%) of 49 eyes with tumors of group C (n=1) and D (n=7); the relapse in 14 of 49 (new lesions on the retina) in eyes with tumors of group C (n=5) and D (n=6) and (new lesions on the retina and the vitreous) in eyes with tumors of group D (n=3) (28.5%), and stabilization of disease n=23 (46.9%). We should note that 2 patients underwent repeated course of in case of systemic chemotherapy, 1 patient — a Gamma Knife procedure due to registered disease stabilization, progression or relapse.Results.10 (20.4%) of 49 eyes saved due to the combined chemotherapy. In 45 patients diseasefree survival rate was 56.1±8.9 % (with mean follow-up period 26.9±2.5 months). 1 of 45 patients died from leukemia. 44 of 45 patients are alive without metastasis. The mean follow-up was 20 months (3 to 43 months). Eye salvage rate in group C — 14 (93.3%) of 15, in group D — 31 (91.2%) of 34.Conclusion.These methods: second line of systemic chemotherapy, RT, and a Gamma Knife procedure should be considered as a failure of primary treatment. Our study demonstrated a high efficacy of local chemotherapy with promissing techniques of conservation therapy, which safety increases due to experience.