Treatment outcome of anaplastic ependymoma under the age of 3 treated by intensity-modulated radiotherapy

Abstract

Purpose: Intensity-modulated radiotherapy (IMRT) allows for more precise treatment, reducing unwanted radiation to nearby structures. We investigated the safety and feasibility of IMRT for anaplastic ependymoma patients below 3 years of age.

Materials and methods: A total of 9 anaplastic ependymoma patients below 3 years of age, who received IMRT between October 2011 and December 2017 were retrospectively reviewed. The median equivalent dose in 2 Gy fractions was 52.0 Gy (range, 48.0 to 60.0 Gy). Treatment outcomes and neurologic morbidities were reviewed in detail.

Results: The median patient age was 20.9 months (range, 12.1 to 31.2 months). All patients underwent surgery. The rates of 5-year overall survival, freedom from local recurrence, and progression-free survival were 40.6%, 53.3%, and 26.7%, respectively. Of the 9 patients, 5 experienced recurrences (3 had local recurrence, 1 had both local recurrence and cerebrospinal fluid [CSF] seeding, and 1 had CSF seeding alone). Five patients died because of disease progression. Assessment of neurologic morbidity revealed motor dysfunction in 3 patients, all of whom presented with hydrocephalus at initial diagnosis because of the location of the tumor and already had neurologic deficits before radiotherapy (RT).

Conclusion: Neurologic morbidity is not caused by RT alone but may result from mass effects of the tumor and surgical sequelae. Administration of IMRT to anaplastic ependymoma patients below 3 years of age yielded encouraging local control and tolerable morbidities. High-precision modern RT such as IMRT can be considered for very young patients with anaplastic ependymoma.

Keywords: Ependymoma; Intensity-modulated radiotherapy; Local neoplasm recurrence; Morbidity; Pediatrics.

Fig. 1.

Comparison of three-dimensional conformal radiotherapy (A) versus intensity-modulated radiotherapy (B) in the treatment of brain tumor. The difference between preservation of optic chiasm, brainstem, and both cochlear among treatment plans can be compared visually to some extent.

Fig. 2.

Comparison of dose volume histograms between three-dimensional conformal radiotherapy (dotted line) and intensity-modulated radiotherapy (solid line). The planning target volume (PTV) in blue, optic chiasm in pink, brainstem in yellow, right cochlear in light green and left cochlea in orange.

Fig. 3.

Kaplan-Meier curves of overall survival (A), freedom from local recurrence (B) and progression-free survival (C) in patients with anaplastic ependymoma.