Seventy‐two patients with retinoblastoma (RTB) (unilateral [47 patients] and bilateral [25 patients]) were studied for a period of 6 years. Treatment consisted of enucleation of those eyes that had severe involvement and was followed by radiation therapy and/or chemotherapy (systemic or intrathecal) according to clinical pathologic staging. All patients who underwent nonsurgical treatment received systemic chemotherapy. Intrathecal chemotherapy was administered when there was involvement of the central nervous system. Nonsurgical treatment consisted of radiation therapy and/or light coagulation, followed by enucleation if there was no response. The overall survival rates were 79% for unilateral disease (median follow‐up time, 63 months) and 72% for bilateral disease (median follow‐up time, 81 months). Vision was regained in 14 of 21 conserved eyes.

During 4 years, 51 patients with retinoblastoma were studied (unilateral 32, and bilateral 19). Treatment consisted of enucleation of those eyes which showed massive involvement followed by radiotherapy when there was optic nerve and/or orbit involvement. Systemic chemotherapy was administered to all patients who underwent nonsurgical treatment and when the histologic examination showed choroidal optic nerve head and/or optic nerve involvement or residual tumor after enucleation. When there was compromise of the central nervous system intrathecal chemotherapy was administered. Nonsurgical treatment consisted of radiotherapy and/or light coagulation. Survival was 90.6% for unilateral cases and 84.2% for the bilateral. The median follow-up was 31 months and 29 months, respectively. Of 19 conservated eyeballs, 16 preserve useful vision (63%).

RESUMENObjetivo: Evaluar la importancia de la detección de mutaciones del gen RB1 en el asesoramiento gené-tico de las familias argentinas con retinoblastoma. Métodos: Se incluyeron en este estudio 34 familias argentinas con Retinoblastoma (Rb) bilateral y unilateral. Se analizaron 130 muestras de ADN de leucocitos, tumores y vellosidades coriónicas, por ensayos de Biología Molecular indirectos y directos, como Southern blot, segregación de los polimorfismos BamHI, Rbi4, XbaI y Rb 1.20 (PCR-RFLP, PCR-STR), PCR-heteroduplex y secuenciación del gen RB1. Resultados: El análisis molecular fue informativo en 18 familias de las 34 incluidas en el estudio (53%), el 56% con Rb bilateral y el 44% con Rb unilateral. Se contó con muestras de ADN tumoral de 11 pacientes que se estudiaron para detectar pér-dida de heterocigosidad (LOH), que posibilitó identificar el alelo RB1 mutado en 9 pacientes (82%). Cuando no se analizaron las muestras tumorales, ABSTRACTObjective: Evaluate the relevance of RB1 mutations detection in the genetic counselling of Argentine retinoblastoma families. Methods: We included in this study 34 Argentine families with bilateral and unilateral Retinoblastoma (Rb). 130 DNA samples from leukocytes, tumors and chorionic villus were analyzed by indirect and direct molecular biology assays like Southern blot, segregation of polymorphisms BamHI, Rbi4, XbaI y Rb 1.20 (PCR-RFLP, PCR-STR), PCR-heteroduplex and sequencing of RB1 gene. Results: Molecular biology analysis was informative in 18 out of 34 families studied (53%), 56% with bilateral and 44% with unilateral Rb. DNA tumor samples of 11 patients were available and could be studied by loss of heterozygosity (LOH) detection, that allowed us to identify the mutated RB1 allele in 9 (82%) patients. When tumor samples were not analized, the studies were informative only in 9 out of 23 patients (39%); we used direct mutation