SUPERSELECTIVE OPHALMIC ARTERY INFUSION FOR RETINOBLASTOMA

October 25, 2010 (Chicago, Illinois) — A new chemotherapeutic approach that has shown success as a last resort for advanced retinoblastoma is demonstrating "dramatic" results as an initial treatment for this pediatric eye cancer. Results of the experimental treatment — superselective ophthalmic artery infusion of chemotherapy — were presented here at the American Academy of Ophthalmology and Middle East Africa Council of Ophthalmology 2010 Joint Meeting.

"This treatment, which is really chemosurgery, has enabled us to eliminate the use of most systemic chemotherapy [in newly diagnosed patients] and to completely eliminate the use of radiation," said presenter David Abramson, MD, chief of the Ophthalmic Oncology Service at Memorial Sloan-Kettering Cancer Center in New York City.

"We have been able to salvage more than 90% of the chemotherapy-naïve eyes," he said at the meeting.

Dr. Abramson gave an update on his team's experience with the new approach, also called direct intra-arterial chemotherapy. It involves an interventional radiologist inserting a catheter into the femoral artery, threading it up to the ophthalmic artery, and infusing chemotherapy locally. The procedure is done on an outpatient basis with the patient under general anesthesia; the mean number of treatments is 3, according to Dr. Abramson.

Patients receiving initial treatment with intra-arterial chemotherapy experience "a dramatic reduction in the tumor in less than 3 weeks," Dr. Abramson said. Some children who were blind in the retinoblastoma-affected eye or eyes were able to visually track after treatment, their parents reported.

Most often the chemotherapy is single-agent melphalan (less than 0.5 mL), but some patients also receive topotecan or carboplatin if their tumors are more advanced, he said. The researchers use a low dose of melphalan, but because it is concentrated at the eye, the dose is 100 to 1000 times more potent than that for systemic chemotherapy, Dr. Abramson told Medscape Medical News. However, it reportedly eliminates the severe systemic toxic effects that accompany the intravenous infusion of chemotherapy.

"No patient has significant systemic toxicity," he said. "Not one child has had to have a transfusion [of any blood products], which is amazing."

Cure Is Possible

"Initially, we thought we'd be happy if we only prevented the effects of systemic chemotherapy," Dr. Abramson said. "But soon we realized we were onto something more exciting — a cure."

Since the first patient with retinoblastoma received intra-arterial chemotherapy in May 2006, more than 100 patients have received the treatment, and no patient has died, according to Dr. Abramson. In eyes that needed enucleation, it was because of progression of advanced disease, not ocular complications of the procedure, he said. Furthermore, among children whose cancer did not recur in the first few months after treatment, none have had a recurrence, he told Medscape Medical News.

As a result of the promising findings, the research team expanded the study protocol from treating only eyes in which treatment had failed — where the only option was enucleation — to treating patients who had undergone no previous chemotherapy. They ended up treating 28 eyes of 23 patients with newly diagnosed retinoblastoma. The results of the study were published in the August issue of Ophthalmology (2010;117:1623-1629).

"Giant Step Forward"

"This is a giant step forward in the treatment of retinoblastoma," David Telander, MD, PhD, a panelist at the symposium where Dr. Abramson presented his research, told Medscape Medical News. "It's going to revolutionize treatment for these kids."

Dr. Telander, assistant professor of ophthalmology at the University of California at Davis, did not participate in the research, which he called "exciting," given its reported effectiveness and limited adverse effects.

Dr. Abramson said that ocular toxicity from the procedure is rare in chemotherapy-naïve eyes; that in eyes that have previously undergone chemotherapy, the main potential complication is intraocular bleeding and vitreous hemorrhage.

Because there are fewer complications than after systemic chemotherapy, the cost of treatment is half that of standard chemotherapy, Dr. Abramson told Medscape Medical News.

However, other researchers have cautioned that physicians do not yet know whether direct intra-arterial chemotherapy is toxic to the retinal vessels (Clin Experiment Ophthalmol. 2010;38:638-643).

Infants younger than 3 months are not candidates for the procedure, according to Dr. Abramson.

Dr. Abramson has disclosed no relevant financial relationships. Dr. Telander reports receiving consulting fees and/or honoraria from Allergan, Eyetech, Genentech, and OD-OS.

American Academy of Ophthalmology (AAO) and Middle East Africa Council of Ophthalmology (MEACO) 2010 Joint Meeting: Late Breakers Symposium SYM33. Presented October 19, 2010.