Initial treatment of IDH-mutant astrocytoma (grades 2, 3, and 4) in adults

IDH: isocitrate dehydrogenase; MRI: magnetic resonance imaging; WHO: World Health Organization; RT: radiation therapy; PCV: procarbazine, lomustine, vincristine.

* Modest amounts of residual grade 2 tumor after surgery, even measuring >1 to 2 cm, may be reasonably observed in some cases, provided that the patient is asymptomatic from the tumor aside from well-controlled epilepsy.

¶ Patients who are uncomfortable with the uncertainties of observation may reasonably choose immediate postoperative therapy, even though this approach is associated with more side effects in the short term. In addition, individual risk factors (eg, age >40 years, preoperative tumor volume ≥4 cm, neurologic deficits) are sometimes used to select patients for immediate further therapy after gross total resection. Practice in this area varies among experts. Refer to UpToDate topic on treatment of IDH-mutant astrocytomas for further details.

Δ Selection is individualized. Both temozolomide regimens are considered appropriate by expert groups for grade 4 IDH-mutant astrocytomas, and comparative evidence in these tumors is not available. There is no evidence to support one regimen as "more aggressive" than another in terms of efficacy, and the risk of hematologic toxicity may be higher with concurrent therapy, particularly in females.