[Conservative therapy for retinoblastoma--effect of melphalan on in vitro electroretinogram]

The effect of melphalan (an alkylic anti-cancer drug) on rabbit and human in vitro ERGs was studied to establish the non-toxic concentration of melphalan in chemo-thermotherapy for retinoblastoma. The ERGs were recorded before and 15 min after the perfusate was changed from the control solution to a melphalan-containing solution. Melphalan 10 micrograms/ml and 40 micrograms/ml caused no significant effect on the a-wave, the b-wave, or the oscillatory potential in either the rabbit or the human in vitro ERG. Melphalan 50 micrograms/ml significantly reduced the b-wave, but the change was reversible. Considering the minimum inhibitory concentration of melphalan against retinoblastoma cells on colony assay (4 micrograms/ml), melphalan is one of the most effective drugs for the conservative treatment of retinoblastoma.