In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 41, No. 16_suppl ( 2023-06-01), p. e14035-e14035
Abstract:
e14035 Background: Patients with Grade 2 IDH mutated astrocytoma that have residual disease after surgery are characterized as high risk. There is limited data to guide timing of treatment for these patients so treatment guidelines recommend either adjuvant chemoradiation or observation delaying adjuvant treatment until disease progression (OBS). This study sought to evaluate the clinical characteristics and survival of patients with Grade 2 IDH mutated astrocytoma treat with adjuvant temozolomide (TMZ) based chemoradiation (tRT) compared to patients treated with observation following surgery. Methods: We conducted a multicenter retrospective study of patients with histologic grade 2 IDH mutated astrocytoma treated at the University of Washington and Stanford Medical Center. To evaluate the impact of treatment, tRT was defined as treatment decision at time of diagnosis to treat with radiation in combination with concurrent and or adjuvant TMZ. Extent of resection and progression were determined based on the treating neuro-oncologists notes. Survival probability, overall survival (OS) and time to first progression (PFS), were calculated using Kaplan-Meier method with distributions compared using log-rank test in GraphPad Prism. Results: A total of 115 patients were identified with a median follow up of 6.54 years (y). For the whole cohort, median overall survival (mOS) was 15.5y and median progression free survival (mPFS) was 4.9y. For the whole cohort, 29 patients were treated with tRT and 58 with OBS. tRT improved PFS compared to OBS (p=0.044) with mPFS 6.17y v. 3.58y. There was no difference in OS (p=0.11) as the mOS for tRT was 12.8y v. 15.5y. For the patients with residual disease after surgery, 24 patients were treated with tRT and 26 with OBS with a median follow up of 5.3y. Treatment with tRT trended towards improved PFS (6.2y) compared to OBS (3.5y) (p=0.061). There were no significant difference in demographics of these high risk patients. For OBS patients, 6 had tRT at progression in the range of 0.9y to 25.4y and median time of 2.4y. Conclusions: This multicenter retrospective study found that for Grade 2 IDH mutated astrocytoma, tRT treatment following surgery with residual disease improved PFS but did not impact mOS. However in high risk patients, tRT did not impact either PFS or OS. This study further confirmed the protracted natural history of this disease and supports observation as a treatment option for patients with Grade 2 IDH mutated astrocytoma, even for high risk patients who underwent biopsy or subtotal resection. [Table: see text]
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/JCO.2023.41.16_suppl.e14035
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2023
detail.hit.zdb_id:
2005181-5
