Intravitreal Melphalan versus Topotecan for Vitreous Seeds in Retinoblastoma

Purpose

To compare the outcomes of intravitreal melphalan (IVit-M) versus intravitreal topotecan (IVit-T) for vitreous seeds (VS) in retinoblastoma (RB).

Design

Retrospective interventional study.

Participants

Patients of RB with VS receiving intravitreal chemotherapy (IVit-C) between December 2012 and December 2022, at a single quaternary ocular oncology referral center.

Intervention

Intravitreal melphalan injection of 25 μg/0.1 mL in 25 eyes and IVit-T of 30 μg/0.15 mL in 39 eyes.

Main Outcome Measures

Resolution of VS, globe salvage, IVit-C–related complications.

Results

The mean age at presentation was 28 months (median, 24 months; range, 4–144 months) for the IVit-M group and 25 months (median, 24 months; range, 2–60 months) for the IVit-T group. At the time of initiation of intravitreal injection, the VS belonged to type 1 (1 [4%] vs. 1 [3%]), type 2 (9 [36%] vs. 14 [36%]), type 3 (8 [32%] vs. 18 [46%]), or a combination of these (7 [28%] vs. 6 [15%]) in IVit-M and IVit-T groups, respectively. Complete resolution of VS after IVit-C was seen in 22 (92%) and 28 (72%) eyes (P = 0.069) in IVit-M and IVit-T groups, respectively. At a mean follow-up period of 44 months after the first IVit-C injection in the IVit-M group and 19 months in the IVit-T group, globe salvage was higher in the IVit-T group (77%) than in the IVit-M group (60%, P = 0.148), respectively. Posterior segment complications were significantly higher in the IVit-M group than in the IVit-T group (P < 0.001). These included retinal pigment epithelial atrophy (P < 0.001), optic atrophy (P < 0.001), vascular attenuation (P < 0.001), and retinal/subretinal hemorrhages (P = 0.004).

Conclusions

Intravitreal topotecan is as efficacious as IVit-M for controlling VS in RB, with a better safety profile in pigmented Asian Indian eyes.

Financial Disclosure(s)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.