In low-grade diffuse glioma — specifically astrocytoma that is IDH-mutant and 1p19q non-codeleted (CNS WHO grade 2) — patients with favorable prognostic factors, or where toxicity concerns argue against upfront adjuvant treatment, may reach a decision point after surgery where radiation and chemotherapy have been or can be deferred. A structured, evidence-based protocol applies to this scenario.
Astrocytoma, IDH-mutant, 1p19q non-codeleted, CNS WHO grade 2 (low-grade diffuse glioma) after one or more surgeries. Favorable prognostic factors — such as complete resection or younger age — or concerns about the short- and long-term toxicity of immediate adjuvant treatment support deferral of radiation and chemotherapy. This pathway excludes patients who are pregnant, breast feeding, or seeking pregnancy.
The evidence-based protocol for this scenario involves vorasidenib. The complete regimen — including patient selection criteria, monitoring requirements, and clinical decision points — is available in the full protocol.
DOI: 10.1200/JCO-25-00250
In astrocytoma, IDH-mutant, 1p19q non-codeleted, CNS WHO grade 2, initial radiation therapy and chemotherapy (with temozolomide or PCV) may be deferred until radiographic or symptomatic progression in some people with favorable prognostic factors (eg, complete resection, younger age) or concerns about short- and long-term toxicity given the natural history of the disease.
Vorasidenib may be offered to people with astrocytoma, IDH-mutant, 1p19q non-codeleted, CNS WHO grade 2, where, after one or more surgeries, further treatment with radiation and chemotherapy has been or can be deferred (Evidence quality: High; Strength of recommendation: Conditional).
People who are seeking pregnancy as either father or mother and people who are pregnant or breast feeding should not be offered vorasidenib.
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