IDH-mutant (IDHm) WHO grade 3 or 4 astrocytomas carry a better prognosis than their IDH-wild type (IDH-wt) counterparts. These patients tend to live significantly longer than the IDH-wt. Current NRG consensus guidelines call for a 2 cm expansion over the GTV1 (T2/Flair) and GTV2 (cavity and any resi...