CNSC-25. TUMOR VOLUME REDUCTION ENABLING SURGICAL SALVAGE: HYPOFRACTIONATED RADIOTHERAPY SEQUENTIAL WITH SUPERSELECTIVE INTRA-ARTERIAL CHEMOTHERAPY IN RECURRENT/REFRACTORY HIGH-GRADE GLIOMAS

Abstract BACKGROUND Salvage surgery for recurrent high-grade gliomas (rHGG) is often limited by diffuse tumor infiltration. We explored hypofractionated radiotherapy (HFRT) followed by superselective intra-arterial chemotherapy (SIAC) to reduce tumor volume and facilitate resection. METHODS Four patients with histologically confirmed rHGG (WHO Grade III-IV) and diffuse recurrence received HFRT (30 Gy/10 fractions in 2 weeks) followed by SIAC (teniposide 50mg/m2 d14). Surgical resection was performed 3–4 weeks post-chemoradiation. Outcomes included safety (CTCAE v5.0), radiographic response (RANO criteria), and pathologic downgrading. RESULTS All patients completed therapy without grade ≥3 toxicity (no myelosuppression, hepatorenal/cardiac dysfunction). One patient experienced transient blurred vision during SIAC. Preoperative imaging showed T1 reduction (3/4), T2/FLAIR reduction (2/4), and stable disease (remainder). KPS improved in all patients without steroid escalation. RANO assessments: 1 partial response (PR), 3 stable disease (SD) (100% disease control rate). Post-resection pathology revealed WHO Grade III (1/4), IV (3/4). CONCLUSION HFRT-SIAC is a safe and feasible bridge to surgery in select rHGG patients, inducing tumor volume reduction and enabling salvage resection. Pathologic downgrading in 50% (2/4) suggests potential biologic modulation. Larger studies are warranted to validate this approach.