Management of retinoblastoma with proximal optic nerve enhancement on MRI at diagnosis

Abstract

In North America, retinoblastoma rarely presents with gross clinical evidence of tumor involving the optic nerve. Extent of microscopic tumor infiltration into the postlaminar optic nerve is a significant risk factor for metastasis, especially if there is tumor at the cut end. Due to poor outcomes in patients with metastatic disease, historical treatment for patients with clinical evidence of extraocular optic nerve involvement has included upfront enucleation followed by aggressive adjuvant chemotherapy. Additional orbital irradiation is advocated for individuals with optic nerve involvement at the surgical margin. Little is known about the role of neoadjuvant therapy in the setting of orbital optic nerve enhancement on magnetic resonance imaging (MRI) at diagnosis. A retrospective review of consecutive retinoblastoma cases at Childrens Hospital Los Angeles over a 3-year period (2004-2006) found to have gadolinium contrast enhancement in the proximal portion of optic nerve on MRI at diagnosis. Nine patients fit the inclusion criteria. Two had secondary glaucoma of a sufficient degree to cause an enlarged eye (buphthalmos). Median age at presentation was 17 months (2-36 months). All patients received neoadjuvant chemotherapy prior to enucleation. Only two received external beam radiation. All are disease-free with a median follow-up of 22 months (12-41 months). Neoadjuvant chemotherapy is well tolerated prior to enucleation of retinoblastoma-containing eyes associated with contrast enhancement of the proximal optic nerve on MRI at diagnosis. Such an approach may be used to decrease intensity or duration of chemotherapy and need for external beam radiation.