RADT-24. PHASE II STUDY OF PROTON RADIATION THERAPY FOR LOWER GRADE GLIOMAS

Abstract PURPOSE To report preliminary results on outcomes of patients with lower grade gliomas (LGG) treated proton therapy. METHODS Patients II or IDH mutant III glioma and indications for radiation therapy were enrolled in a prospective single arm trial (PRT), receiving dose 54 Gy(RBE) 59.4 Gy(RBE), respectively. Comprehensive baseline regular post-treatment evaluations neuroendocrine function, neurocognitive functions (NCF), quality life (QOL), progression-free survival (PFS) performed. RESULTS Among 60 (median age 40.8) who received PRT, 28 (47%) men, 39 (65%) WHO II. Eighteen (30%) mutant+1p/19q co-deleted, 36 (60%) astrocytoma, 6 (10%) wildtype. Treatment was at initial diagnosis (41; 68%) progression (19; 32%). Median follow-up after PRT 4.1 years. All current data are reported 3 years from PRT. PFS 86% all patients, 84% (n = 39), 90% favorable 21). 83% 94% co-deleted oligodendrogliomas. New endocrine dysfunction detected (5%). There one 4 case brain necrosis (2%) but no toxicities. NCF decline, defined by Z-score drop >/= 1SD clinical trials battery composite, occurred 7% 3/43). QOL assessment FACT-Brain showed 16% decline 10 points 7/43). CONCLUSIONS At post-treatment, LGG have high PFS, similarly to previous reports photon therapy, few new deficiencies, modest treatment toxicities, minimal QOL. These positive may be attributable limited integral the use demonstrating its value long expectations.