Work

Innv-09. Impact of Molecular Markers on Treatment Outcome of Glioblastoma Patients Treated With Concurrent Tumor-treating Fields (ttf) and Chemoradiation: Secondary Analysis of Spare Trial

Year: 2022

Type: article

Abstract: OBJECTIVES SPARE trial (Scalp-sparing radiation with concurrent temozolomide and tumor treating fields; NCT03477110) is a single-arm pilot study that evaluated the safety and feasibility of concurrent TTF with chemoradiation for adult patients with newly diagnosed GBM. The current study is a secondary analysis evaluating the impact of molecular markers (PTEN, TP53, EGFR, and TERT) on overall survival (OS) and progression-free survival (PFS) of the patients in the trial. METHODS Molecular markers of histologically-confirmed, IDH-wildtype GBM patients age ≥ 18 years old with a KPS ≥ 60 who received concurrent chemoradiation and TTF followed by maintenance TMZ + TTF were evaluated. Molecular profile was evaluated with next-generation sequencing. Impact of mutations in PTEN, TP53, EGFR, and TERT on OS and PFS was evaluated using a multivariable backward model. RESULTS A total of 30 patients were enrolled in the SPARE trial, and 1 patient with IDH-mutant was excluded from the current analysis. All patients underwent concurrent TTF and chemoradiation. The median age is 58 and KPS was 90. 9 patients had methylated MGMT promotor. 14 patients were found to have PTEN mutation, 9 patients with EGFR, 7 with TP53 mutation, and 23 patients with TERT mutated. MGMT methylation remained statistically significant for an increased OS (p=0.032; HR 7.18). TERT mutation had a statistically significant improvement in PFS (P=0.003) and OS (p=0.012). However, neither EGFR, TP53, nor PTEN showed any association of PFS or OS for patients who received concurrent TTF and CRT. CONCLUSIONS In this secondary analysis, patients with MGMT methylation showed better PFS and OS as expected. Neither EGRF, TP53, or PTEN mutation showed any association with PFS or OS. Patients with TERT mutant showed improved OS of patients treated with concurrent TTF with chemoradiation. A TERT mutation may be a new molecular biomarker in the described treatment approach.

Source: Neuro-Oncology

DOI: 10.1093/neuonc/noac209.549