EPEN-06. CHEMOTHERAPY OF RECURRENT EPENDYMOMA: LONG-TERM RESPONSE ONLY IN FEW CASES

INTRODUCTION: The efficacy of chemotherapy in recurrent ependymoma is unclear. We present results from the German HIT-REZ-studies. METHODS: 137 patients were analyzed regarding the treatment with chemotherapy at first recurrence, the time from first relapse to progression (PFS) and to either time-point of death or last follow-up (OS). Tumor response evaluation was based on MRI and clinically; molecular data was available in 80. RESULTS: In our cohort, 96 patients (20 supratentorial, 73 infratentorial, 3 spinal) received chemotherapy during first recurrence: 49 (51.0%) temozolomide (TMZ) monotherapy, 12 (12.5%) HIT-SKK regime, 9 (9.4%) carboplatin/etoposide (CE) and 26 (27.1%) other combinations. In 19.8% (26.5% in TMZ), chemotherapy was administered prior to surgery (neoadjuvant), which resulted in tumor progression in 78% (85% in TMZ). Gross-total resection was achieved in 86% without neoadjuvant chemotherapy and in 74% (69% in TMZ) with neoadjuvant treatment. Switching to trofosfamide/etoposide (TE) after surgery and unresponsiveness to TMZ showed further progression in all cases of tumor-residuum after surgery. Regarding 1-year-PFS, treatment with HIT-SKK (50.0%±14.4%) or CE (55.6%±16.6%) was advantageous over TMZ (30.2%±6.7%). However, 5-y-OS was lower in CE (19.0% ±16.8%) than in TMZ (39.8%±7.7%) and HIT-SKK (42.9%±8.7%). Long-term control was seen in individual cases of TMZ, HIT-SKK and CE, with TMZ providing longest response of 72 months. CONCLUSION: Neoadjuvant TMZ has no significant advantage regarding PFS. However, in few cases chemotherapy prevented progression after incomplete resection. Difficulties in response evaluation and variability in therapies hinder conclusions. Supported by the German Children’s Cancer Foundation