Stage II includes: cT4a, cN0, cM0, Any H. cT4a: Radiologic evidence of retrobulbar optic nerve involvement or thickening of optic nerve or involvement of orbital tissues. cN0: No regional lymph node involvement. cM0: No signs or symptoms of intracranial or distant metastasis. HX: Unknown or insufficient evidence of a constitutional RB1 gene mutation. H0: Normal RB1 alleles in blood tested with demonstrated high-sensitivity assays. H1: Bilateral retinoblastoma, retinoblastoma with an intracranial primitive neuroectodermal tumor (i.e., trilateral retinoblastoma), patient with family history of retinoblastoma, or molecular definition of a constitutional RB1 gene mutation. (AJCC 8th ed.) [from NCI]