Transgender individuals are underrepresented in neuro-oncology research. Little is known regarding the impact of GAHT on CNS tumor outcomes. 

Twelve patients (median age 29; sex assigned at birth: 8 male, 4 female) with glioblastoma (n=1), IDH-mutant astrocytoma (n=2), oligodendroglioma (n=2), ependymal tumors (n=2), pituitary adenoma (n=2), NF2-associated schwannoma/meningioma (n=1), and diffuse glioma with BRAF-V600E mutation (n=1) were included. Eight received feminizing GAHT (estrogen) and four masculinizing GAHT (testosterone). .  

Tumor-directed treatments included surgery (n=10), radiation therapy (n=6), and systemic therapy (n=7, using temozolomide, lomustine, ivosidenib, vorasidenib, lapatinib, bevacizumab). No increase in tumor treatment-related adverse events attributable to GAHT use were noted.. 

Six patients initiated feminizing GAHT before tumor diagnosis (median exposure 32 months, range:13-50) and continued GAHT after tumor identification. Within this group, only one patient with glioblastoma experienced tumor progression during follow up.  

Conclusions GAHT was well tolerated and not associated with accelerated tumor progression in most cases. The temporal association between estrogen exposure and symptom fluctuation in an NF2-associated meningioma highlights the need for individualized risk assessment and multidisciplinary care in this understudied population.