Impact of extent of surgical resection on survival outcomes in patients with IDH-mutant anaplastic astrocytomas and IDH mutant anaplastic oligodendrogliomas: A SEER database study.

Abstract

e14037 Background: Anaplastic astrocytomas and oligodendrogliomas are high-grade gliomas with unique molecular profiles. Molecular markers, such as IDH mutation and 1p/19q co-deletion, influence prognosis and treatment. However, the impact of surgical extent in IDH mutant anaplastic gliomas remains unclear. We investigated how gross total resection (GTR), subtotal resection (STR), or no resection influences overall survival (OS) and cancer-specific survival (CSS), in addition to other treatment and disease parameters. Methods: Data were obtained from the SEER Research Data, 17 registries, Nov 2023 submission (2000-2021). Patients with IDH mutant anaplastic astrocytomas and oligodendrogliomas of the brain were included. Patients with resection of tumor in spinal cord or nerve or without data on surgical extent were excluded. Kaplan-Meier survival analysis and log-rank tests evaluated OS and CSS at 24 months. Results: 871 patients were studied. Median follow-up was 21 months. 56.7% were male. There were 8 American Indian/Alaska Native patients, 70 Asian, 745 White, 40 Black patients and 8 with unknown race. Radiation significantly improved OS (84.7% vs. 66.7%, log-rank p < 0.0001) and CSS (86.1% vs. 71.6%, log-rank p < 0.0001). Surgical resection improved OS: 93.1% for GTR, 80.4% for STR, and 37.7% for no resection (log-rank p < 0.0001). CSS followed a similar pattern: 95.3% for GTR, 81.9% for STR, and 39.9% for no resection (log-rank p < 0.0001). Chemotherapy was associated with better OS (86.2% vs. 59.8%, log-rank p < 0.0001) and CSS (87.3% vs. 65.7%, log-rank p < 0.0001). Tumor type alone did not significantly predict OS (log-rank p = 0.0645), but CSS was higher for oligodendrogliomas (87.3%) compared to astrocytomas (82.0%, log-rank p = 0.0152). In both tumor types, GTR yielded the best OS (92.4% for oligodendrogliomas and 93.5% for astrocytomas, log-rank p < 0.0001). Conclusions: We found that receipt of radiation, receipt of chemotherapy and more complete resection all individually improved OS and CSS. Tumor type showed no significant differences in OS, but CSS favored oligodendrogliomas over astrocytomas. These findings highlight the importance of extent of resection and multimodal treatment strategies in optimizing survival outcomes for patients with IDH-mutant anaplastic gliomas.