2209 - Why Two are Better than One: Combined Modality Salvage Therapy's Effects on Outcomes in Recurrent Glioblastoma
Presenter(s)
A. Shahid1,2, B. Wan2, V. Panet-Raymond2, C. Tsien2, K. Petrecca3, R. Jose Diaz4, S. Owen5, J. Hall6, P. Carrera-Garcia7, C. Couturier7, and B. S. Abdulkarim2; 1Mcgill University, Montreal, Canada, 2Department of Radiation Oncology, McGill University Health Centre, Montreal, QC, Canada, 3Neurosurgery-McGill University, Montreal, QC, Canada, 4Montreal Neurological Hospital-Institute, Montreal, QC, Canada, 5McGill University Health Centre, Montreal, QC, Canada, 6Montreal Neurological Hospital, Montreal, QC, Canada, 7McGill University, Montreal, QC, Canada
Purpose/Objective(s): Recurrent glioblastoma (rGBM) remains a major therapeutic challenge, with poor survival despite multiple salvage options. While repeat surgery and re-irradiation are commonly employed, the optimal approach at recurrence is not clearly defined. This study evaluates outcomes following different salvage strategies.
Materials/Methods: We conducted a retrospective cohort study of patients with rGBM treated between 2015 and 2024. Eligible patients had previously received standard chemoradiotherapy at initial diagnosis and, at recurrence, underwent either radiation or surgery alone or combined modality treatment.
Results: A total of 166 patients were analyzed. Median age was 57 years, with male predominance (N=91). Median overall survival (OS) from initial diagnosis was 25 months. MGMT promoter methylation was associated with improved survival (33 vs 22 months). Younger age (<60 years) predicted better outcomes (P=0.006 HR 0.628). Median time to recurrence was 12 months. The median post-recurrence survival for the entire cohort was 10 months. Recurrence more than one year from completion of RT had significantly improved OS compared to those recurring less than one year after RT (36 and 17 months respectively P <0.001, HR 3.501) and a median post-recurrence survival of 13 vs 8 months (P=0.008, HR 1.550). Patients treated with combined surgery and re-irradiation (n=50) achieved superior post-recurrence survival compared with either surgery (n=92) and radiation alone (n=24) [15 vs 8 months, P=0.016, HR 0.508]. Radiation necrosis occurred in a minority of re-irradiated patients and was significantly more frequent in those who did not receive bevacizumab (p value <0.001).
Conclusion: Combined modality treatment with surgery and re-irradiation at recurrence provides superior survival outcomes compared with single-modality approaches in appropriately selected patients with rGBM. These findings support combined salvage therapy as the preferred treatment strategy at recurrence, particularly in patients with good performance status, favorable molecular profiles, and longer time to recurrence.