Intravitreal Chemotherapy

Intravitreal chemotherapy was described as a treatment for retinoblastoma in the 1960s but was abandoned because of an association with extraocular tumor spread. The technique was re-introduced in 2012 with critical safety measures added to the procedure; this modality now is regarded as a highly effective adjuvant therapy for vitreous seeding. The safety measures include anterior ultrasonographic imaging to ensure that the injection is not made into a quadrant containing active tumor, reduction of intraocular pressure before the injection by means of anterior chamber paracentesis or ocular massage to prevent vitreous reflux, and cryotherapy during withdrawal of the injecting needle to kill any active tumor cells. The safety-enhanced technique is nearly 100% effective for vitreous seeding, and there have been no reports of extraocular tumor spread. Nevertheless, great care and attention to the safety precautions is imperative.

For most eyes, treatment is carried out in 3–6 injections based on the amount and type of seeding. Melphalan, the most frequently used agent for this purpose, is known to induce chorioretinal toxicity. Though not usually visually significant, this toxicity has been severe in some cases. Topotecan has also been used. Other adverse events associated with intravitreal injection include cataract, retinal detachment, and endophthalmitis. If any of these complications occur in a patient with retinoblastoma, enucleation may be required because intraocular surgery rarely is performed, given the risk of orbital seeding of active tumor. See Video 19-1 for a demonstration of intravitreal injection for retinoblastoma.

Courtesy of Jesse L. Berry, MD.

Go to www.aao.org/bcscvideo_section04 to access all videos in Section 4.

• Berry JL, Bechtold M, Shah S, et al. Not all seeds are created equal: seed classification is predictive of outcomes in retinoblastoma. Ophthalmology. 2017;124(12):1817–1825.

• Francis JH, Abramson DH, Ji X, et al. Risk of extraocular extension in eyes with retinoblastoma receiving intravitreous chemotherapy. JAMA Ophthalmol. 2017;135(12):1426–1429.

• Munier FL, Gaillard MC, Balmer A, et al. Intravitreal chemotherapy for vitreous disease in retinoblastoma revisited: from prohibition to conditional indications. Br J Ophthalmol. 2012;96(8):1078–1083.

Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.