Abstract
Purpose: :
To monitor retinal function after superselective intraarterial chemotherapy for retinoblastoma by electroretinography.
Methods: :
Patients with advanced retinoblastoma have been treated at our institution with super-selective intra-arterial chemotherapy since May, 2006. Their retinal function has been monitored by serial electroretinography (ERG). ERGs were obtained during routine examinations under anesthesia using sevoflurane. After clinical evaluation, including indirect ophthalmoscopy, fundus imaging, and ultrasound, an ERG-jet contact lens electrode was inserted in one eye, and photopic ERGs recorded using ISCEV-standard stimuli with the Espion-2 electrodiagnostic instrument and ColorBurst hand-held mini-ganzfeld flash stimulator. The contact lens was transferred to the fellow eye, and ERGs recorded. After 5 minutes of dark adaptation, scotopic ERGs were obtained from the two eyes in succession. [According to standard adaptation curves, this protocol should recover scotopic ERG amplitudes 80-90% as large as those obtained under ISCEV-standard conditions. The reduced adaptation time was dictated by scheduling concerns and the need to minimize the duration of general anesthesia.]
Results: :
We summarize ERG findings after three years of experience, based on the first 61 eyes of 53 patients treated by intra-arterial chemotherapy. 8 patients had both eyes treated ("tandem therapy"). ERG data are available for 58 eyes. Mean follow-up was 7 months. As ERG response amplitudes to different stimulus modalities (photopic and scotopic) tracked each other closely, only representative amplitudes of responses to 30-Hz photopic flicker are listed below. At last recording, ERGs were extinguished in 15 eyes; ERGs were poor (less than 25 microvolts) in 8 eyes; fair (25.1 -50. microvolts) in 8 eyes; good (50.1 - 75 microvolts) in 7 eyes; and excellent (at least 75.1 microvolts) in 20 eyes. Compared with pre-treatment baseline, 17 eyes had reduced ERG amplitudes, 29 eyes were unchanged, and 12 eyes were improved.
Conclusions: :
Super-selective intra-arterial chemotherapy for retinoblastoma is compatible with retention of retinal function, with preservation or improvement of ERG amplitudes observed in over 2/3 of cases.
Clinical Trial: :
www.clinicaltrials.gov NCT00901238
Keywords: electroretinography: clinical • retinoblastoma