title: Retinoblastoma: might photodynamic therapy be an option?
abstract: Retinoblastoma is a tumor that mainly affects children under 5 years, all over the world. The origin of these tumors is related with mutations in the RB1 gene, which may result from genetic alterations in cells of the germ line or in retinal somatic cells. In developing countries, the number of retinoblastoma-related deaths is higher due to less access to treatment, unlike what happens in developed countries where survival rates are higher. However, treatments such as chemotherapy and radiotherapy, although quite effective in treating this type of cancer, do not avoid high indices of mortality due to secondary malignances which are quite frequent in these patients. Additionally, treatments such as cryotherapy, thermotherapy, thermochemotherapy, or brachytherapy represent other options for retinoblastoma. When all these approaches fail, enucleation is the last option. Photodynamic therapy might be considered as an alternative, particularly because of its non-mutagenic character. Photodynamic therapy is a treatment modality based on the administration of photosensitizing molecules that only upon irradiation of the tumor with a light source of appropriate wavelength are activated, triggering its antitumor action. This activity may be not only due to direct damage to tumor cells but also due to damage caused to the blood vessels responsible for the vascular supply of the tumor. Over the past decades, several in vitro and in vivo studies were conducted to assess the effectiveness of photodynamic therapy in the treatment of retinoblastoma, and very promising results were achieved.
authors.affiliation: Unit of Biophysics, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Teixo
authors.affiliation: Unit of Biophysics, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal. mafaldalaranjo@fmed.uc.pt.|CIMAGO, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal. mafaldalaranjo@fmed.uc.pt.|IBILI, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal. mafaldalaranjo@fmed.uc.pt.
authors.forename: Mafalda
authors.initials: M
authors.lastname: Laranjo
authors.affiliation: Unit of Biophysics, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal.|CIMAGO, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal.|IBILI, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal.
authors.forename: Ana Margarida
authors.initials: AM
authors.lastname: Abrantes
authors.affiliation: Unit of Biophysics, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal.
authors.forename: Gonçalo
authors.initials: G
authors.lastname: Brites
authors.affiliation: Chemical Engineering Department, Faculty of Science and Technology, University of Coimbra, Pólo II, Pinhal de Marrocos, 3030-290, Coimbra, Portugal.
authors.forename: Arménio
authors.initials: A
authors.lastname: Serra
authors.affiliation: IBILI, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal.|Centre for Integrated Responsibility in Ophthalmology, Coimbra Hospital and University Centre (CRIO-CHUC), Praceta Mota Pinto, 3000-075, Coimbra, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Proença
authors.affiliation: Unit of Biophysics, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal.|CIMAGO, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal.|IBILI, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal.
authors.forename: Maria Filomena
authors.initials: MF
authors.lastname: Botelho
mesh_terms: D002675:Child, Preschool; D006801:Humans; D010778:Photochemotherapy / Q000009:adverse effects / Q000379:methods*; D017319:Photosensitizing Agents / Q000009:adverse effects / Q000627:therapeutic use*; D012175:Retinoblastoma / Q000628:therapy*; D016160:Retinoblastoma Protein / Q000235:genetics
chemical_list: D017319:Photosensitizing Agents; D016160:Retinoblastoma Protein
keywords: Cancer therapy; Photodynamic therapy; Photosensitizers; Retinoblastoma