Abstract

BACKGROUND: In 2016, the World Health Organization (WHO) revised its guidelines to retain only gemistocytic astrocytoma (GemA) as a distinct variant of diffuse astrocytoma (DA). In the past, grade 2 GemAs have been linked with a worse prognosis than DA. However, it is unclear how consistently the tumor subtype has been diagnosed over time. We used more recent data to compare outcomes between grade 2 GemA and DA.METHODS: WHO grade 2 DA and GemA patients were extracted from the SEER database between 1973-2016. Kaplan-Meier curves estimated survival differences across different eras, with a focus on patients diagnosed between 2000-2016, and propensity score matching (PSM) was used to balance baseline characteristics between DA and GemA cohorts RESULTS: Of 2,467 grade 2 astrocytoma patients between 2000-2016, 132 (5.35%) were diagnosed with GemA, and 2,335 (94.65%) were diagnosed with DA. At baseline, marked demographic and treatment differences were noted between tumor subtypes, including age of diagnosis and female sex. GemA patients did not have worse survival compared to DA patients at baseline (p=0.349) or after PSM (p=0.497). Multivariate Cox models found that surgical extent of resection was associated with a survival benefit for DA patients, and both DA and GemA patients aged >65 years had dramatically inferior survival.CONCLUSIONS: Our data suggest that the impact of GemA versus DA histopathology depends more upon the decade of queried data rather than patient-specific demographics. Using more recent longitudinal data, we found that grade 2 GemA and DA tumors did not have significant differences in survival. These data may prove useful for clinicians counseling patients diagnosed with grade 2 GemA.

View details for DOI 10.1016/j.wneu.2021.11.089

View details for PubMedID 34844008