title: Ineffective photodynamic therapy (PDT) in a poorly vascularized xenograft model.
abstract: Haematoporphyrin derivative (HPD) photodynamic therapy (PDT) may have clinical application in the management of patients with retinoblastoma. Heterotransplantation of retinoblastoma cells into the anterior chamber of the nude mouse eye and the subsequent growth of small tumour masses has provided a model for evaluation of various therapeutic modalities. Ninety-four evaluable xenograft tumours in 54 nude mice were randomized to receive one of the following treatments: cyclophosphamide (CPM) alone, HPD-PDT alone, CPM followed by HPD-PDT, HPD-PDT followed by CPM, or saline control. Responses were demonstrated after CPM treatment in all three relevant groups. However, HPD-PDT was found to be ineffective either alone or as a contributor in the double modality treatment groups. The small tumour masses treated can be demonstrated histologically to be avascular. It is proposed that although the same retinoblastoma cells in different circumstances are responsive to HPD-PDT, no clinical response is demonstrable utilizing this model, due to the absence of tumor vascularity.
authors.affiliation: Prince of Wales Children's Hospital, Randwick, Sydney, NSW, Australia.
authors.forename: L
authors.initials: L
authors.lastname: White
authors.forename: C J
authors.initials: CJ
authors.lastname: Gomer
authors.forename: D R
authors.initials: DR
authors.lastname: Doiron
authors.forename: B C
authors.initials: BC
authors.lastname: Szirth
mesh_terms: D000818:Animals; D003131:Combined Modality Therapy; D003520:Cyclophosphamide / Q000627:therapeutic use; D004195:Disease Models, Animal; D005134:Eye Neoplasms / Q000098:blood supply / Q000188:drug therapy*; D006414:Hematoporphyrin Photoradiation; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010778:Photochemotherapy; D012175:Retinoblastoma / Q000098:blood supply / Q000188:drug therapy*; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D003520:Cyclophosphamide