Intravitreous Chemotherapy as Adjuvant Treatment for Vitreous Seeding in Retinoblastoma: A Philippine Tertiary Hospital Experience

Abstract

Background. Intravitreal chemotherapy has been an effective addition in treating vitreous seeding in retinoblastoma. However, it was only in 2020 that it was used in the Philippines. There is no literature on its use in multiple Filipino retinoblastoma patients.

Objectives. To describe the clinical course of the four patients who are the first to undergo intravitreal chemotherapy for vitreous seeding of retinoblastoma in the Philippine tertiary hospital.

Methods. A case series of four eyes of four patients with retinoblastoma who underwent intravitreous injection
of melphalan and topotecan for vitreous seeding at the Department of Ophthalmology and Visual Sciences of a
Philippine tertiary hospital.

Results. Two eyes, with International Intraocular Retinoblastoma Classification (IIRC) Group C with vitreous seeding, responded well to intravitreous melphalan and topotecan. One eye had recurrent vitreous seeding despite 10 intravitreal injections. One eye with IIRC Group E, did not respond to intravitreous chemotherapy and was eventually enucleated.

This is the first case series on the local use of intravitreous chemotherapy in the country for vitreous seeding in
retinoblastoma. The control of 50% achieved in this case series is lower than in other series due to longer treatment interval from poor follow-up and the presence of advanced disease.

Conclusion. The use of intravitreous melphalan and topotecan can be an effective adjuvant for systemic chemotherapy in controlling vitreous seeding in eyes with IIRC Group C. It is not effective in controlling IIRC Group E disease.