Reirradiation for Recurrent Pediatric CNS Malignancies: A Multi-Institutional Review

Publication date: Available online 29 July 2017
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Avani D. Rao, Arif Rashid, Qinyu Chen, Rosangela C. Villar, Daria Kobyzeva, Kristina Nilsson, Karin Dieckmann, Alexey Nechesnyuk, Ralph Ermoian, Sara Alcorn, Shannon M. MacDonald, Matthew M. Ladra, Eric C. Ford, Brian A. Winey, Maria Luisa S. Figueiredo, Michael J. Chen, Stephanie A. Terezakis
PurposeReirradiation has been proposed as an effective modality for recurrent CNS malignancies for adults. We evaluated toxicity and outcomes of CNS reirradiation in pediatric patients.Methods and MaterialsPediatric patients age <21 years at time of initial diagnosis who developed a recurrent CNS malignancy treated with repeat radiation therapy (RT) across 5 facilities in an international pediatric research consortium were retrospectively reviewed.ResultsSixty-seven pediatric patients were treated with CNS reirradiation. Primary diagnoses included medulloblastoma/primitive neuroendocrine tumor (n=20, 30%), ependymoma (n=19, 28%), germ cell tumor (n=8, 12%), high grade glioma (n=9, 13%), low grade glioma (n=5, 7%), and other (n=6, 9%). Median age at first course of RT was 8.5 years (range:0.5-19.5 years) and 12.3 years (range:3.3-30.2 years) at time of reirradiation. The median time interval between RT courses was 2.0 years (range: 0.3-16.5). Median dose and fractionation of RT in equivalent 2 Gy fractions (EQD2) was 63.7 Gy (range 27.6-74.8 Gy) for initial RT and 53.1 Gy (range 18.6-70.1 Gy) for repeat RT. Location of relapse was infield in 52 patients (78%) and surrounding initial RT field in 15 patients (22%). Thirty-seven patients (58%) underwent gross- or sub-total resection at time of recurrence. Techniques for reirradiation were IMRT (n=46), 3D-CRT (n=9), SRS (n=4, 12-13Gyx1 or 5 Gyx5), protons (n=4), combined modality (n=3), 2D-RT (n=1), and brachytherapy (n=1). Radiation necrosis was detected in 2 cases after first course of RT and 1 additional patient after reirradiation. Six patients (9%) experienced secondary neoplasms following initial RT (1 hematologic, 5 intracranial neoplasms). One patient developed a secondary neoplasm identified shortly after repeat RT. Median overall survival following end of reirradiation was 12.8 months in the entire cohort and 20.5 and 8.4 months for patients with recurrent ependymoma and medulloblastoma following reirradiation.ConclusionsCNS reirradiation in pediatric patients may be a reasonable treatment option with moderate survival noted following repeat RT; although, prospective data characterizing rates of local control and toxicity are needed.

Teaser

This is a unique study evaluating the treatment parameters, toxicity, and outcomes of pediatric CNS reirradiation through a multi-national, multi-institutional pediatric research consortium. Low rates of radiation necrosis were observed and patients experienced reasonable survival rates following repeat radiation therapy to recurrent CNS tumors that may justify the risks of reirradiation.


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