Clinical efficacy and prognostic factors of postoperative adjuvant radiotherapy for pediatric ependymoma / 中华放射肿瘤学杂志

ABSTRACT

Objective:To investigate the clinic opathological features, treatment and prognosis of children newly diagnosed with ependymoma.Methods:Clinical data of 127 pediatric ependymoma (EPN) patients (0-16 years old) treated with tumor resection and postoperative radiotherapy at Xinhua Hospital Affiliated to Shanghai Jiao Tong University between 2001 and 2021 were retrospectively analyzed. Among them, 53 children were female and 74 were male. Local control (LR), event-free survival (EFS) and overall survival (OS) rates were analyzed by Kaplan-Meier method. The relationship between clinic opathological factors and clinical prognosis, and the effect of treatment on clinical prognosis of patients were analyzed by Cox proportional hazards model.Results:At a median follow-up time of 29 months (3-251 months), the 3-year OS and EFS rates were 89.5% and 71.5%, respectively. For patients undergoing incomplete resection followed by postoperative adjuvant radiotherapy, the 3-year LR, OS and EFS rates were 78.3%, 65.8% and 85.7%, respectively. A total of 43 children were aged <3 years old when diagnosed and 84 aged ≥3 years old. The interval time between surgery and radiotherapy in children aged <3 years old was 91 d, and 35.5 d in those aged ≥3 years old ( P<0.001). For patients <3 years old, the median EFS was 90 months when initiating radiotherapy within ≤70 d after surgery, compared to 43 months for those who initiated radiotherapy at >70 d after surgery ( P=0.053). According to fifth edition of the WHO classification of tumors of the central nervous system (WHO CNS5), 39 children were classified as posterior fossa ependymoma group A (PFA group). The OS and EFS rates in the PFA group were significantly less than those in other groups (3-year OS rate were 69.2% vs. 94.6%, P<0.001; 3-year EFS rate were 46.9% vs. 79.1%, P<0.001). In the PFA group, 12 patients received postoperative adjuvant chemotherapy, 14 did not receive chemotherapy, and whether chemotherapy was given was unknown in 13 cases. No significant differences were observed in OS and EFS between patients treated with and without chemotherapy ( P=0.260, P=0.730). Univariate Cox analysis showed that tumor location and WHO CNS5 molecular classification were significantly associated with EFS, and WHO CNS5 molecular classification was significantly correlated with OS. Multivariate Cox analysis showed that tumor location in the posterior fossa was an independent risk factor for EFS ( HR=2.72, 95% CI=1.1~6.71, P=0.03). Conclusions:Patients newly diagnosed with pediatric ependymoma can obtain favorable survival after surgery combined with postoperative adjuvant radiotherapy. Patients with residual tumors can achieve favorable LC and survival after postoperative adjuvant radiotherapy. Delaying of radiotherapy tends to lead to poor survival for patients aged <3 years old when diagnosed. Children in the PFA group obtain worse prognosis compared to their counterparts in other groups. The tumor location in the posterior fossa is an independent risk factor for pediatric ependymoma.