FEB 03, 2014
Retina/Vitreous
This systematic review found that significant ocular complications following intravitreal injection therapy (IViT) for retinoblastoma are uncommon, and this risk may be further reduced by the use of careful injection technique and standard dosing regimens.
The authors reviewed results from 10 studies with original data on intravitreal injection therapy for retinoblastoma. There was a combined total of 1,287 intravitreal injections given to 306 eyes of 295 patients, with a mean follow-up of 74.1 months. Two hundred sixty-one patients received comparatively standard melphalan doses (8 to 30 mcg).
Ocular side effects occurred in 38 patients (17 significant, 21 minor). Three percent of patients (8/261) experienced potentially significant ocular side effects following standard melphalan IViT regimens. Side effects in these eight patients included iris atrophy in three, chorioretinal atrophy in two, vitreous hemorrhage in two and retinal detachment in one.
Of the other nine patients with significant complications, five sight-threatening complications followed dramatic dose escalations (four with melphalan, one with thiotepa), three experienced complications commonly associated with concurrent therapies, and one had a retinal detachment. Of the 61 patients who received treatment via safety-enhancing injection techniques, all six significant side effects were attributable either to dosage or concurrent treatments.
The authors write that using melphalan doses of less than or equal to 30 mcg can minimize the risk of intraocular toxicity. Animal studies should be used to guide the dosing of less commonly injected antineoplastic agents to further reduce this risk. Also, ultrasound biomicroscopy prior to injection may help reduce risk of retinal detachment, and injecting under microscopic visualization may further reduce the risk of lens damage and tumor cell contact.