Electroretinogram monitoring of retinal toxicity of ophthalmic artery chemosurgery for retinoblastoma: Six year experience

Abstract

 

Purpose

 

The effectiveness of ophthalmic artery chemosurgery (OAC) for retinoblastoma derives from the very high local tissue concentrations achieved in the distribution of the ophthalmic artery, before the drug is safely diluted in the systemic venous circulation. We have recorded electroretinogram (ERG) responses before and after OAC to monitor retinal function as a gauge of local toxicity, and we herein report these results.

 

Methods

 

Prospective review of 6-year experience of retinoblastoma patients receiving OAC. This study recorded the ERG 30 Hz flicker amplitude response changes from baseline, at 3 and 12 months following treatment completion. Inclusion criteria consisted of eyes treated with OAC with ERG measurements a. before OAC, and b. 3 months after the last OAC treatment +/- 1 month, and if available, c. 12 months after last OAC treatment +/- 2 months. Both univariate and multivariate linear regression models were performed, with generalized estimating equations to correct for correlations within patients. Independent numerical variables included maximum and cumulative doses of melphalan, topotecan and carboplatin.

 

Results

 

ERG data were available for 103 eyes of 81 patients; a total of 270 recordings were analyzed. Results from the univariate and multivariate regressive analysis are shown in figures 1 and 2, respectively.

 

Conclusions

 

Melphalan has the strongest, and carboplatin the weakest association to change in ERG response. By univariate analysis, both melphalan and topotecan appear to be associated with changes in ERG amplitude at both 3 and 12 months; but for the most part, these changes are minimal and likely clinically insignificant. By multivariate analysis, maximum and cumulative melphalan have a modest, temporary effect on the ERG amplitude change, which is apparent at 3 months but no longer evident at 12 months after completing treatment. By multivariate analysis, topotecan and carboplatin do not appear to adversely effect the change in ERG response.

 

 

Univariate regression analysis

 

 

Multivariate regression analysis

 

Keywords: 703 retinoblastoma • 744 tumors • 503 drug toxicity/drug effects