Treatment of Childhood Myxopapillary Ependymoma

Myxopapillary ependymoma, considered to be a histological subtype of ependymoma, has a relatively high incidence of central nervous system (CNS) tumor dissemination at diagnosis and at follow-up. Imaging of the complete craniospinal axis at the time of diagnosis and during follow-up is indicated.[1,2] According to the 2021 World Health Organization (WHO) Classification of Tumors of the CNS, myxopapillary ependymoma is now considered WHO grade 2 rather than grade 1 because its recurrence rate is similar to conventional spinal ependymoma and exceeds the rate typical of grade 1 tumors.[3]

Standard treatment options for newly diagnosed childhood myxopapillary ependymoma include the following:

Historically, the management of myxopapillary ependymoma consisted of an attempt at en bloc resection of the tumor with no further treatment in the case of a gross-total resection.[4]; [5][Level of evidence C2] However, some practitioners now favor the use of radiation therapy after surgical resection of the primary mass. This practice is based on the finding that dissemination of these tumors to other parts of the neuraxis can occur, particularly after partial resection, and evidence that focal radiation therapy may improve progression-free survival (PFS).[1,4]; [6-8][Level of evidence C2]

With the exception of an en bloc gross-total resection where the utility of adjuvant radiation therapy has been debated, radiation therapy is often considered for patients with less than a gross-total resection, a piecemeal resection, or locally recurrent disease after surgery alone. A retrospective single-institution review included 18 pediatric patients with myxopapillary ependymoma.[9]

However, two reports provided some support for the use of radiation therapy for patients with multifocal spinal myxopapillary ependymoma. The first study included 12 children (aged <21 years) who were treated with limited-volume brain-sparing proton radiation therapy. The median age of patients was 13.5 years. Radiation therapy was given as adjuvant therapy after primary surgery in five patients and for recurrence in seven patients. No patient had previously received radiation therapy. Of the 12 patients, 11 (92%) had evidence of gross disease at the time of radiation therapy, and all but one patient received 54 Gy relative biological effectiveness (RBE) of radiation therapy.[10]

A second multi-institutional retrospective study of 60 pediatric and adolescent and young adult (AYA) patients also suggested a benefit of radiation therapy (2000–2020). The median age at radiation therapy was 14.8 years (range, 7.1–26.5 years). The population was high risk because the indications for radiation therapy included gross residual disease, microscopic residual disease, or recurrent or multifocal disease.[11]