Executive summary of American Radium Society’s appropriate use criteria for the postoperative management of lower grade gliomas

Postoperative management of lower grade gliomas (grade 2 and 3) is heterogeneous. The American Radium Society's brain malignancies panel systematically reviewed and evaluated the literature to develop consensus guidelines addressing timing of postoperative therapy, monotherapy versus combined modality therapy, type of chemotherapy used with radiotherapy, and radiotherapy dose. Thirty-six studies were included. Using consensus methodology (modified Delphi), the panel voted upon representative case variants using a 9-point appropriateness scale to address key questions. Voting results were collated to develop summarized recommendations. Following gross-total surgical resection, close surveillance is appropriate for well-selected grade 2, IDH-mutant oligodendrogliomas or astrocytomas with low-risk features. For grade 2 gliomas with high-risk features or any grade 3 glioma, immediate adjuvant therapy is recommended. When postoperative therapy is administered, radiation and planned chemotherapy is strongly recommended over monotherapy. For grade 2 and 3 IDH-mutant oligodendrogliomas and astrocytomas, either adjunctive PCV (procarbazine, lomustine, vincristine) or temozolomide is appropriate. For grade 3 IDH-mutant astrocytomas, radiotherapy followed by temozolomide is strongly recommended. The recommended radiotherapy dose for grade 2 gliomas is 45-54 Gy/1.8-2.0 Gy, and for grade 3 gliomas is 59.4-60 Gy/1.8-2.0 Gy. While multiple appropriate treatment options exist, these consensus recommendations provide an evidence-based framework to approach postoperative management of lower grade gliomas.