Objective: The purpose of this study was to review the assessment of residual tumor, analyze surgical factors associated with incomplete resection, determine the risk of neurological sequelae for reoperation, and assess the impact of second surgeries on survival.

Methods: Patients 0-21 years old with nonmetastatic intracranial ependymoma treated within the prospective multicenter E-HIT2000 trial were included. Prospective central neuroradiological review of pre- and postoperative imaging was performed.

Results: The 291 patients included in the E-HIT2000 trial underwent surgery at 71 centers in Germany, Austria, and Switzerland. Timely central review of postoperative imaging of sufficient quality was performed in 206 patients, and extent of resection was classified as gross-total resection (GTR) in 137 (67%) patients and incomplete with residual disease (RD) in 69 (33%) patients. Surgeons erroneously reported GTR in 11/40 patients with RD and available surgical reports; adhesions in the rhomboid fossa and/or brainstem were the most common reasons for intentional RD. Twenty-three of the 69 patients with RD underwent a second surgery as part of their primary treatment, 11 before and 12 after the start of adjuvant therapy; in 11/23 patients, GTR was achieved after a maximum of 3 procedures. The frequency of postoperative neurological deficits in the patients with second surgery did not differ from that in patients with primary GTR. Ten-year overall survival with GTR was 69.8% ± 4.4% versus 51.2% ± 7.1% with RD (p = 0.002). A second surgery significantly improved progression-free survival (42.4% ± 11.5% vs 22.2% ± 6.5% without second surgery, p = 0.004).

Conclusions: Second surgery was not associated with an increased frequency of neurological sequelae and conferred an advantage in survival overall. The authors strongly recommend early central neuroradiological review to evaluate postoperative residual tumor and discuss reoperation. Further studies are needed to outline a tailored risk assessment for each patient based on molecular and clinical aspects.