Intra-arterial Chemotherapy as Primary Treatment for Cavitary Retinoblastoma: Excellent Response in Eight Tumors

Abstract

The "cavitary" form of retinoblastoma has historically demonstrated minimal treatment response with intravenous chemoreduction, showing less robust regression and less reduction in tumor size. Intra-arterial chemotherapy (IAC) has been reported to more effectively treat retinoblastoma, allowing many previously unsalvageable eyes to now be saved. The purpose was to report treatment response of cavitary retinoblastoma tumors to IAC. Retrospective case series. Patients presenting with cavitary retinoblastoma who were treated with IAC. Retrospective case series of all patients presenting with cavitary retinoblastoma between August 2014 and January 2019 who were treated with primary IAC. Tumor regression, recurrence, resolution of vitreous and subretinal seeds, number of treatments required, globe salvage, metastasis, and death. Eight cavitary retinoblastoma tumors in 6 eyes of 4 patients were treated with IAC. One hundred percent of the cavitary tumors regressed (8/8 tumors, in 6/6 eyes), and 100% of vitreous and subretinal seeds regressed, with 100% globe salvage. None of the tumors recurred, no patients developed metastases, and no patients died. Eyes were treated with a median of 4.5 cycles of IAC (range, 1-7), with fewer IAC treatments used in the later patients (1-3 treatments per eye for the most recent 3 eyes, compared with 6-7 treatments per eye for the earliest 3 eyes). Mean reduction in thickness was 73.4% (range, 59.7%-84.6%). Mean reduction in basal diameter was 45.5% (range, 24.8%-56.0%). Treatment with IAC results in regression of cavitary retinoblastoma, often with greater reduction in tumor size than has been reported previously with intravenous chemotherapy (IVC). Using up-front triple therapy (e.g., melphalan 0.4 mg/kg, carboplatin 50 mg, and topotecan 2 mg) and noting certain subtle signs of early regression can help to minimize unnecessary additional cycles of treatment.