Management outcome(s) in eyes with retinoblastoma previously inadequately treated with systemic chemotherapy alone without focal therapy

Objective: The objective of this study was to evaluate the outcome of management in eyes with intraocular retinoblastoma (RB) that had received inadequate initial therapy (chemotherapy without focal therapy) before eventually receiving necessary consolidation therapy at a tertiary referral center.

Methods: A retrospective observational case series of 30 eyes from 26 RB patients who had initially received systemic chemotherapy as a sole therapy. The main outcome measures were demographics, laterality, International Classification of RB (ICRB), treatments, tumor control, and survival.

Results: The median age at diagnosis was 24 months and the median delay between time at diagnosis and time at referral to a tertiary center that has adequate focal therapy for RB was 9.5 months (range 5-20 months). Sixteen (62%) patients were monocular from enucleation of the contralateral eye. Features of ICRB Group A tumors were seen in 3 (10%) eyes, Group B in 7 (23%) eyes, Group C in 2 (7%) eyes, Group D in 16 (53%) eyes, and Group E in 2 (7%) eyes. Eighteen (69%) patients required more systemic chemotherapy (median, 4.4 cycles; range, 2-8 cycles), and 8 (26%) eyes received local chemotherapy (subtenon, intravitreal, or intra-arterial). All treated eyes received consolidation therapy as transpupillary thermotherapy and/or cryotherapy. Radioactive plaque therapy was used in 1 (3%) eye and external beam radiation therapy in 3 (10%) eyes. At a mean follow-up of 13 months (median, 11.5 months; range, 9-27 months), enucleation was avoided in 25 (83%) eyes. Two (7%) eyes were enucleated initially, and 3 (10%) were enucleated after failure of additional therapy. Twenty-three (77%) eyes did not show any viable tumor after a median of 11.5 months of follow-up after the last treatment, and 2 (7%) eyes still have residual tumor recurrences that need more consolidation focal therapy.

Conclusion: Chemotherapy alone cannot eradicate RB cells in effected eyes without combination with consolidation therapy by a multidisciplinary team to salvage the affected eye as well as its vision. Nonetheless, chemotherapy can be initiated (to keep the tumor at a less invasive stage) for patients from centers or countries where combination therapy is not available until they gain access to adequate management of RB.