Efficacy of vincristine and carboplatin as chemo-reduction for advanced bilateral retinoblastoma, the Saudi experience

To evaluate the efficacy of a 2-drug chemotherapy regimen without external-beam radiotherapy (EBRT) and/or without enucleation in bilateral retinoblastoma. From 1996 to 2010, 79 patients were diagnosed with bilateral RB and were eligible for chemotherapy. Chemotherapy was administered prior to and/or following local therapy to the eye. All patients received 3 cycles of chemo-reduction with carboplatin and vincristine, additional cycles of the same or other chemotherapy, local therapy, EBRT and enucleation were determined according to re-evaluation by the ophthalmologist. Advanced disease was seen in 115 (79%) eyes (group IV and V: 96, Group D and E: 19) out of 146 affected eyes. Tumor response after chemotherapy was observed in 78 patients (98.7%); complete response in 25 (32.1%), partial response in 49 (62.8%) Four (5.1%) had progressive disease. A total of 50 (63.3%) patients required EBRT; 38 for persistent disease, 4 for progressive disease, 2 for new lesions, 2 for re-activation and 4 for disease control. Enucleation was required in 15 (19%). Secondary malignancies occurred in two patients who underwent EBRT; one osteogenic sarcoma and one rhabdomyosarcoma then later osteogenic sarcoma. The 10year overall survival was 96.3% with a median follow-up time of 3.124±0.536years (95%CI: 2.074–4.174). The 2-drug chemotherapy regimen combined with local therapy appears to be adequate therapy for low stage disease but not in patients with advanced disease. The occurrence of secondary cancers in this group of patients is worrisome further highlighting the deleterious effects of EBRT.