Tissue concentrations of doxorubicin in animal models with engrafted intraocular tumours.

The role of chemotherapy in the management of retinoblastoma remains unclear. In order to evaluate the responsiveness to conventional or experimental agents, a xenograft model had been developed, where human retinoblastoma is heterotransplanted to the anterior chambers of nude mouse eyes. Because doxorubicin had been found to be ineffective in therapeutic studies utilizing the model, experiments were conducted to evaluate the concentration of the drug in tissues, including intraocular engrafted tumour. The presence of doxorubicin was demonstrated in xenograft containing mouse eyes as well as in tumours of a comparable rabbit model. Distribution in extraocular tissues was consistent with previously published data. It is concluded that failure of response to doxorubicin in the xenograft model is not explained by lack of tumour penetration by the drug.