Efficacy of intravitreal injections of melphalan in the treatment of retinoblastoma vitreous seeding

Background. The introduction of intravitreal injections of melphalan (IVIM) has significantly improved the efficacy of retinoblastoma treatment and the prognosis for eye preservation. Objectives. To evaluate the results of using IVIM to treat retinoblastoma vitreous seeding. Materials and methods. This was a clinical, retrospective, single-center study. Twenty-six children (27 eyes) who met all of the following inclusion criteria qualified for the study: 1) active vitreous seeding at the time of retinoblastoma diagnosis; 2) IVIM performed between 1 January 2017 and 30 September 2020; and 3) a minimum follow-up period of 12 months since the last IVIM. Doses of 20-40 mu g melphalan per injection were used. Results. The eye observation period from the last IVIM to the last ophthalmic examination averaged 32.41 months (median 30.00; range 13.00-56.00). Success (no active tumors in the vitreous body) was achieved in 24 eyes (88.9%), and a doubtful result (recurrence in the retina with a difficult-to-determine etiology) in 2 eyes (7.4%). In 1 eye (3.7%), despite treatment, active tumors were still present in the vitreous body. Out of all 27 eyes, 4 eyeballs were removed, but the direct cause of enucleation was not vitreous seeding. There were no complications in the form of intraocular inflammation, extraocular retinoblastoma or distant metastases. There was 1 case of anterior uveitis and 1 case of cataract. Conclusions. The IVIM is a highly effective and safe form of treatment for retinoblastoma vitreous seeding.