Outcomes of patients with bilateral retinoblastoma: A report from the RIVERBOAT Consortium.

10045 Background: Retinoblastoma (RB) is the most common tumor of the eye in childhood. Intraocular RB cure rates approach 100%. Therefore, treatment advances have focused on globe salvage preserving functional vision. The Research Into Visual Endpoints and RB Health Outcomes After Treatment (RIVERBOAT) consortium was established to examine patient health outcomes, including vision, in the contemporary therapy era. Methods: Patients with RB treated at consortium centers from 2007 to the present were identified. Medical record abstraction was performed for disease presentation, treatment, and outcomes. A subset of the patients returned to centers and completed functional vision questionnaires (Child Vision Function Questionnaire for ages 0 – 7 and Cardiff Visual Ability Questionnaire for Children for ages >8) and had visual acuity assessed. For participants who could not yet return for a study evaluation, medical record abstraction alone was performed. Results: Among 463 participants enrolled to date, 193 (42%) had bilateral disease. Two each had metastatic RB, trilateral RB, and secondary osteosarcoma. One patient each with metastatic RB and trilateral RB is deceased, with overall survival for the cohort of 99%. The eye group distribution (International Intraocular Retinoblastoma Classification) was 14% A, 22% B, 14% C, 28% D, 19% E and 3% not classified. Primary enucleation was performed in 43 (22%), secondary enucleation in 48 (25%) and bilateral enucleation in 1(0.5%). Intravenous chemotherapy (IV) alone was administered in 58%, intra-arterial chemotherapy (IAC) alone in 4%, with 31% receiving both. Among 145 patients who did not require secondary or bilateral enucleation, the distribution was 16% A, 21% B, 16% C, 28% D, 15% E, and 4% non-classified eyes. This salvage was achieved with IV alone, IAC alone, or both in 55%, 5% and 30% respectively and with ophthalmic therapy only in 10%. The mean percentage of patients receiving IAC per year increased from 6% in 2008 – 2013 to 11% in 2014 – 2022 and was stable at 11% in 2018 – 2022. Among 53 patients who have reported functional vision to date, the mean scores were 0.81 for < 3 years 0.80 for 3-7 years and -1.31 for those >8 years, all considered to be good functional vision. Among 50 eyes in 37 of these 53 patients, 33 had normal vision (20/20-20/40) across A to E groups. Moderate vision loss (> 20/40 – 20/70) was noted in 1 C and 1 B eye and low vision (> 20/70 - < 20/200) in 6 group B, C or D eyes. Nine B or D eyes were legally blind (>20/200). No patients had two legally blind eyes. Conclusions: In this cohort of RB patients with bilateral disease treated between 2007 and 2022, 52% have been successfully treated without enucleation. Self-reported functional vision in 53 of these patients with all group eyes was good. Only 6 of 50 eyes in 37 patients met criteria for legal blindness and 66% of eyes had normal vision. With cohort accrual ongoing, we will determine if these promising outcomes continue.