Development of New Solitary Retinoblastoma Tumors during and after Chemotherapy

PURPOSE: To review the occurrence of new solitary tumors during and after intravenous chemotherapy against retinoblastoma. METHODS: From 115 eyes of 78 patients with a diagnosis of intraocular retinoblastoma who underwent intravenous chemotherapy and focal treatment without prior treatment, patient demographics, age at diagnosis, laterality, classification (Reese-Ellsworth and International Classification of Retinoblastoma), and treatment options were recorded. In addition, the occurrence of small tumors during and after chemotherapy was documented with a detailed review of medical records and fundus photographs. RESULTS: Of a total of 115 eyes of 78 consecutive patients, new solitary tumors were observed in 50 eyes (50 / 115, 43%) of 40 patients (40 / 78, 51%). Multinominal logistic regression analyses showed that age at diagnosis (before 1 year) and vitreal seeding at diagnosis were linked to the development of isolated and miliary tumors, respectively. Kaplan-Meier analyses demonstrated that all small tumors developed with 20 months from the start of chemotherapy. Twenty-eight eyes (28 / 34, 82%) were salvaged with additional focal treatment in 34 eyes with isolated tumors. CONCLUSIONS: Small tumors were observed during and after chemotherapy against retinoblastoma in patients who underwent intravenous chemotherapy and focal treatment. It is necessary to promptly identify and address small tumors for the preservation of eyeball and vision.