EPID-09. Delayed surgical intervention in low-grade gliomas: an analysis of the Surveillance, Epidemiology, and End Results (SEER) and the National Cancer Database (NCDB)

INTRODUCTION Despite evidence supporting the benefit of early surgical treatment of low-grade gliomas, the “watchful waiting” approach remains commonly practiced. Here, we examined the real-world pattern of surgical recommendations on early versus delayed surgical biopsies for low-grade gliomas. METHODS Low-grade astrocytoma, anaplastic astrocytoma, and glioblastoma patients who underwent biopsies for histologic diagnosis were identified in the NCDB (2010-2021) and SEER (2004-2019). The early biopsy (EB) cohort was defined as patients receiving a recommendation for biopsy on initial presentation. Patients receiving initial recommendations against surgery were placed in the “watchful waiting”/delayed biopsy (DB) cohort. Demographic, clinical characteristics, and survival outcomes of these cohorts were compared. RESULTS In both the NCDB and the SEER, low-grade gliomas were more likely to receive a DB recommendation than glioblastoma patients after adjusting pertinent covariates. (NCDB: aOR=1.88, p<0.001; SEER: aOR=1.77, p<0.001). Interestingly, anaplastic astrocytoma patients were also more likely to receive DB recommendations than glioblastoma patients (NCDB: aOR=1.97, p<0.001; SEER: aOR=1.78, p<0.001). Variables associated with DB for low-grade glioma and anaplastic astrocytoma patients included: advanced age, deep cortical/infratentorial location, and smaller tumor size. In the NCDB, these findings remain robust after accounting for dehydrogenase (IDH) mutation status, which was available in the NCDB after 2018. In a multivariable model accounting for survival-pertinent variables, including age, tumor location, and tumor size, DB patients showed a higher hazard ratio of death relative to EB patients. For low-grade glioma patients, the aHR=1.23 (p=0.006) for NCDB and aHR=1.15 (p=0.039) for SEER. For anaplastic astrocytoma patients, the aHR=1.44, p<0.001 for the NCDB and aHR=1.53, p<0.001 for the SEER. CONCLUSIONS Patients with low-grade or anaplastic astrocytoma are nearly twice as likely to receive a recommendation for “watchful waiting”/delayed biopsy. This practice should be considered in light of the clinical availability of IDH inhibitors and surgical technologies that improve the safety of stereotactic needle biopsies.