The research suggests, When proper safety precautions are implemented, intravitreous chemotherapy injections into eyes with retinoblastoma are unlikely to trigger extraocular extension of tumor events. The study was appeared in the JAMA Ophthalmology

Dr. Jasmine Francis of Memorial Sloan Kettering Cancer Center in New York City and colleagues wrote “Biopsy or intraocular surgery on these diseased eyes has reportedly resulted in reactivation of tumor necessitating enucleation or leading to orbital and/or systemic metastases.”

 “However, with the adoption of safety-enhanced techniques, the risk of tumor externalization with intravitreous chemotherapy injections is thought to be low,” they add.

To investigate, the team reviewed data on 655 patients (mean age, 32 at the time of initial injections; 53% male) at 10 retinoblastoma centers in North and South America, Europe, Israel and China from 1999 through February 2017. Around 3,553 intravitreous chemotherapy injections were administered to 704 eyes, with no extraocular tumor events related to previous intravitreous injections.

This finding resulted in a calculated proportion of zero extraocular events per eye. According to the rule of 3, a statistical technique for interpreting zero numerators, the risk of extravasation is no greater than 0.08% injections, the authors state in their report. “These data suggest that the occurrence of extraocular tumor in eyes with retinoblastoma receiving intravitreous chemotherapy is possible but unlikely,” they conclude.

They point out that all 10 centers used at least two of the following “presumed precautionary injection methods” – lowering of intraocular pressure, cryotherapy, ocular surface irrigation, ultrasonic biomicroscopy surveillance of the injection site, and subconjunctival chemotherapy deposition. Some of these methods were developed by lead study author Dr. Francis Munier of Jules-Gonin Eye Hospital in Lausanne, Switzerland.

Dr. Jasmine Francis told Reuters Health, “This is an exciting time in the management of retinoblastoma: intravitreal melphalan successfully treats vitreous seeds and saves eyes, and this study now shows that when precautionary techniques are used, the treatment is also safe.”

“This challenges the 35-year period of history – between 1960 and 1995 – when the field was reluctant to inject into retinoblastoma eyes for fear of it being unsafe,” she said . “Despite these findings, sound judgment is recommended when injecting into retinoblastoma eyes, particularly with regard to employing precautionary techniques.”

Study author Dr. Jesse Berry of the University of Southern California, Los Angeles added, “This new approach to treat vitreous seeding has challenged the long-standing dogma that the intraocular space in an eye with retinoblastoma cannot be accessed, and will surely spur an era of new treatments and interventions for our patients.”

Dr. Yu-Guang He, professor of ophthalmology at UT Southwestern in Dallas told Reuters Health he used intravitreal chemotherapy to treat a two-year old girl with advanced retinoblastoma in both eyes. The girl died due to the tumor metastasizing to her brain.

 “Chemotherapy agents potentially could be very toxic to the retina, as well as the lens, cornea and optic nerve,” he concluded. “Therefore, readers should be careful when interpreting the results (of) this study.”