Abstract 100P
Background
Astrocytoma is a primary brain tumour arising from specific glial cells called astrocytes. Isocitrate dehydrogenase (IDH) mutations represent an early oncogenic event in glioma evolution. The 2-hydroxyglutarate builds up and is produced in grade II/III astrocytoma. Adjuvant chemo(radio)therapy is the standard treatment. Optimal treatment strategies are controversial due to the risk-benefit ratio. This study aims to assess the effect of IDH mutation on survival outcomes with different treatment modalities for a better understanding of the disease.
Methods
Data were obtained from the SEER program for patients with diffuse and anaplastic astrocytoma diagnosed from 2018-2020. Patients were divided into wild-type (wIDH) and mutant-type (mIDH) groups and subclassified based on the received adjuvant therapy (chemotherapy, radiotherapy, chemoradiotherapy). All patients had surgery (tumour destruction, local excision, partial, radial, and total gross resection). SPSS 27 was used for statistical analysis, the Kaplan-Meier curve, and the long-rank test for survival analysis.
Results
Out of 811 patients, 486 (59.9%) had mIDH, and 325 (40.1%)had wIDH. The 2-year relative survival for mIDH was 95%, and 51% for the wIDH, P<0.001. The highest 2-year relative survival among the mIDH group was for patients who received adjuvant chemotherapy (100%), compared to adjuvant chemoradiotherapy (95.3%) and adjuvant radiotherapy (81.2%), P=0.051. The 2-year survival for wIDH who received adjuvant chemotherapy, combined adjuvant chemoradiotherapy and adjuvant radiotherapy were 66%, 51% and 42%, respectively; P=0.022.
Conclusions
The mIDH had better 2-year relative survival compared to wIDH across all treatment modalities. Adjuvant chemotherapy had more than 20% survival benefit compared to radiotherapy in mIDH and wIDH. These results suggest adjuvant chemotherapy as the modality of choice for mIDH to improve the survival outcome and avoid radiotherapy's unfavourable side effects.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.