Treatment outcome of osteosarcoma after bilateral retinoblastoma: a retrospective study of eight cases.

AIMS: To analyse clinical characteristics and treatment outcomes of osteosarcoma that developed in survivors of bilateral retinoblastoma.

METHODS: Three institutions participated in this retrospective study. Among survivors of bilateral retinoblastoma who were diagnosed and treated between 1995 and 2012, 8 cases (4 male, 4 female) of osteosarcoma were identified. Medical records were thoroughly reviewed.

RESULTS: Median age at diagnosis of bilateral retinoblastoma was 8.5 months (range 1.4-18.4 months). Treatment modalities for retinoblastoma were: enucleation+chemotherapy+radiotherapy (n=6); chemotherapy combined with focal therapy (n=1); and chemotherapy+radiotherapy (n=1). Median radiotherapy dose was 46.5 Gy (range 45-54 Gy). Median age at diagnosis of osteosarcoma was 8.9 years (range 5.4-20.3 years). Median interval between retinoblastoma and osteosarcoma was 8.2 years (range 5.0-20.0 years). Tumour locations were femur (n=5), tibia (n=1), mandible (n=1), and nasal cavity (n=1). Two patients presented with lung metastasis. Seven patients received multimodal treatment, and treatment was refused in 1 patient. After diagnosis of osteosarcoma, the patients were followed for a median of 17.3 months (range 4.4-56.4 months). The 2-year overall survival and event-free survival rates were 56.3 ± 19.9% and 33.3 ± 18.0%, respectively. At the time of analysis, 5 patients remained alive, and 2 of them were on therapy. Of the 3 surviving patients without evidence of disease, 2 received high dose chemotherapy with autologous peripheral blood stem cell support.

CONCLUSIONS: Our data could be used as a basis for future studies aimed at reaching consensus about long term follow-up and treatment guidelines for this genetically susceptible group of patients.