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 injectionof melphalan and topotecan for vitreous seeding at the Department of Ophthalmology and Visual Sciences of aPhilippine 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 inretinoblastoma. 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.

Philippine retinoblastoma initiative multi-eye center study 2010-2020

“…The survival rate in this series is lower than the overall survival rate of Baguio General Hospital and Medical Center highlighting the importance of providing a more representative data to describe the outcomes of retinoblastoma patients in the country. The survival rate was lower than the series from Pakistan (64%-66%) and India (83%-94%) despite having lesser proportion of Group E disease [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]24,29,[35][36][37] . The survival rates in this series, based on IRSS staging, are also lower compared to a series in South Africa, the only series with survival rates based on IRSS, which were 95% for stage 1, 85% for 2, 50% for 3 and 6% for 4 [38] .…”

“…Higher completion of systemic chemotherapy among bi/tri-lateral cases can be secondary to parents of patients with unilateral disease who thought that since the diseased eye has been enucaleated, compliance to complete the chemotherapy decrease. Intravitreal chemotherapy to address vitreous seeding was already done in three patients included in the series [10] . Many participating institutions do not have equipment for radiotherapy and local therapy (cryotherapy and transpupillary thermal therapy) needed for diseases caught early, especially in the better eye of patients with bilateral disease.…”

“…Of the 277 patients with high-risk features on their enucleated eyes, 10 did not necessitate chemotherapy, 151 completed (55%), 6 were undergoing, 28 did not complete due to death, 57 abandoned, 1 refused, and 24 had no additional data. Three patients underwent additional intravitreal chemotherapy while one patient underwent intracameral chemotherapy using melphalan and topotecan [10] . Although patients with bilateral disease listed the highest survival rate (43%; Table 8), there was no significant difference between the outcomes of patients with unilateral disease and those with bilateral (P=0.49).…”