Regression of cavitary retinoblastoma after intra-arterial chemotherapy and transpupillary thermotherapy

Abstract

A 20-month-old boy presented with a 5-month history of left eye exotropia. Initial fundoscopy revealed multiple retinal tumors in the left eye, prompting referral to our institution. On ocular examination, a large cavitary mass was present in the macula of the left eye. Multiple smaller tumors were seen in the retinal periphery. The right eye was normal. B-scan ultrasound of the left eye showed multiple retinal tumors, with hyperechogenic spots, consistent with calcifications. The largest mass measured 6.2 mm in thickness and 13.8 mm × 13.3 mm in basal diameter. There was no family history of retinoblastoma (RB) or other intraocular tumors, and genetic testing for RB1 revealed no pathologic variants in the blood. The patient was diagnosed with a group D sporadic unilateral multifocal RB, with cavitary features, of the left eye. A decision was made to treat with intra-arterial chemotherapy (IAC), consisting of melphalan, carboplatin, and topotecan. Remarkable response of the peripheral noncavitary masses was observed 3 weeks after a single IAC session; however, the macular cavitary tumor remained unchanged. Transpupillary thermotherapy (TTT) was administered for the macular tumor (850–1200 mW). Significant response of the cavitary tumor was only observed after 4 IAC and 3 TTT sessions. The tumor continued to regress over several months after completion of 5 cycles of IAC and multiple TTT sessions (D). No recurrence has occurred on 30 months of follow-up. Cavitary tumors in RB are historically thought to be chemoresistant, but our case responded well to a combination of IAC and TTT.