Surgical outcomes in high-grade adult type diffuse gliomas (ATDG) with a previous diagnosis of anaplastic astrocytoma without adjuvant therapy

Abstract

Introduction

Gliomas pose a significant treatment challenge due to their varied genetic makeup and clinical presentations. This study examines a unique cohort of high-grade adult type diffuse gliomas (ATDG) previously diagnosed as anaplastic astrocytoma prior to the WHO 2021 tumor classification changes. This cohort chose to undergo only surgical resection without adjuvant therapies. We provide a rare dataset of patients allowing for new insight into the natural progression of this disease with surgical treatment alone.

Methods

A retrospective review was conducted of patients who were operated on by a single surgeon from the years 2002–2022 and who were diagnosed as having a Grade III Anaplastic Astrocytoma before the WHO 2021 guidelines were published. Correcting for the criteria in the 2021 Guidelines resulted in a mixture of adult-type diffuse malignant gliomas (ATDG), including IDH-Mutant astrocytomas (Grade 3 and 4) and IDH-WT Glioblastoma. All patients included underwent surgical resection alone after declining any adjuvant therapy for various reasons.

Results

A total of 20 patients met the inclusion criteria with an average age of 38 years. Among them, 15 had IDH-mutant (IDH-mt) Grade 3 astrocytomas (75 %), 1 had an IDH-mt Grade 4 astrocytoma (5 %), and 4 had IDH-wildtype (IDH-WT) glioblastomas (20 %). The 5-year survival rate for the entire cohort was 74.0 %. Grade 3 astrocytomas had a 5-year survival of 86.7 %, while Grade 4 astrocytomas and IDH-WT GBM patients exhibited a 5-year survival rate of 40 %. 5-year progression-free survival (PFS) rates were derived from the surgery date up until the recurrence or censorship. The collective cohort had a PFS rate of 34.3 %. Grade 3 astrocytomas achieved a 5-year PFS of 32.0 %, whereas Grade 4 astrocytomas and IDH-WT GBM reached a PFS of 40.0 %.

Conclusion

In our cohort study, we demonstrate that patients with ATDG can potentially achieve relative long-term survival through surgical resection alone. This unique cohort highlights the natural progression of this disease with surgery alone and provides the foundation for future more rigorous studies to evaluate the additive benefit of different adjuvant therapies. With evolving tumor classifications and variable responses to standard therapeutics, it becomes imperative to revisit and understand the additive benefits of different chemotherapeutic protocols in addition to surgical resection.