PDT may be ideal for treating circumscribed choroidal hemangioma

August 15, 2005

Cleveland—Verteporfin photodynamic therapy (Visudyne PDT, Novartis Ophthal-mics/QLT Inc.) for symptomatic circumscribed choroidal hemangioma appears to be safe, effective, and associated with potential benefits relative to alternative modalities, said Arun D. Singh, MD.

"Traditional treatments for circumscribed choroidal hemangioma have included laser photocoagulation, cryotherapy, various radiotherapy approaches, and transpupillary thermotherapy. However, the drawback of all of those modalities is their potential to cause damage to the overlying retina. Moreover, even in adequately treated patients, they have been associated with a poor long-term visual prognosis," said Dr. Singh, director, department of ophthalmic oncology, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland.

"Conceptually, PDT is far superior to those methods because it can offer site-specific tumor destruction while sparing the overlying retina and retinal vasculature, and from a practical standpoint, it has the advantage of being able to be performed in the office setting under local anesthesia," he said. "Use of verteporfin PDT for the treatment of circumscribed choroidal hemangioma is off-label and longer-term follow-up from treated patients is needed. However, anatomic and functional outcomes continue to be favorable as experience continues to accumulate."

TAP protocol followed

Verteporfin PDT was performed using the TAP (Treatment of Age-Related Macular Degeneration with Photodynamic Therapy) study protocol. First, verteporfin 6 mg/m2 was administered as an intravenous infusion over 10 minutes. Then, 5 minutes after the infusion ended, the lesion was treated with a 690-nm diode laser using an intensity of 600 mW/cm2 for 83 seconds (50 J/cm2) and a single spot or multiple partially overlapping spots.

Available follow-up for the cohort ranges from 1 to 13 months. The treatment was associated with tumor regression in all eyes, with complete flattening observed in eight eyes and a residual growth measuring about 1.5 mm thick in the remaining two eyes. In addition, subretinal fluid resolution and angiographic reduction of the choroidal vasculature were observed. The two patients with partial tumor regression were re-treated after 4 to 6 months and achieved complete regression.

"We assess the response after 3 weeks. However, because repeat treatment may increase the risk of complications and vision loss, re-treatment is withheld for 3 months and the patient closely monitored if there is still some residual hemangioma," Dr. Singh said.

Visual acuity improved in four eyes and remained stable in four others. Visual acuity worsened within the first month after treatment in one eye and showed delayed worsening in another eye after initial improvement. In both cases, loss of vision was attributed to retinal pigment epithelial/choroidal atrophy associated with application of overlapping spots.

"Based on this experience, we no longer use overlapping spots, which we feel results in application of energy levels that may exceed the safety threshold," Dr. Singh said. "Keeping the spot size small so as to avoid treatment of the normal surrounding choroid is also recommended for minimizing the risk of vision loss."

In his review of the literature, Dr. Singh noted that other groups performing verteporfin PDT to treat symptomatic circumscribed hemangioma have used different protocols varying with respect to the duration of verteporfin infusion, number of treatment sessions, laser power settings, duration of exposures, and number of spots. However, Dr. Singh said he chose to follow the TAP protocol because it is a familiar approach with a proven record in the treatment of exudative AMD.