Background Retinoblastoma is the most common intraocular childhood tumour. Although mortality is low in Western countries, long-term sequelae, including secondary tumours, compromised vision or loss of one or both eyes are common. Chemoreduction combined with focal treatment is currently the leading conservative treatment for retinoblastoma, with success rates of 50–75% reported. We assessed a new chemoreduction protocol using intravenous cyclophosphamide with reduced dose of carboplatin on eye retention in patients with retinoblastoma.

Procedure The 40 patients with retinoblastomas in 56 eyes were treated between 1995 and 2004 at the German Retinoblastoma Reference Centre Essen. The 6-cycle chemotherapy used vincristine (days 1, 22, 43, 64, 85, 106), etoposide (days 22, 43, 85, 106), carboplatin (days 1, 43, 64, 106), and cyclophosphamide (days 1, 22, 64, 85). Mean follow-up was 101 months. Most patients received additional hyperthermia, some received local treatment with laser coagulation, cryotherapy and/or β-ray brachytherapy. Therapy failure was defined as progression requiring enucleation or external beam radiotherapy (EBRT).

Results Primary chemotherapy was successful in 42 of 56 eyes (75%). Therapy success and visual acuity at age 6 years correlated with the International Classification of Retinoblastoma (ICRB) group. Age at diagnosis (> or <6 months) correlated with relapse, but not with therapy failure or visual acuity at 6 years of age. ICRB group did not correlate with occurrence of relapse.

Conclusions In this retrospective single-centre study, chemoreduction, including cyclophosphamide, with or without focal treatment, effectively controlled retinoblastoma progression without requiring enucleation or EBRT. Addition of cyclophosphamide is safe, and allows reduction of carboplatin.