Prognostic impact of blood group O in MGMT-methylated glioblastoma patients receiving radiochemotherapy with temozolomide and lomustine.

PURPOSE: Blood group O has recently been associated with improved survival in patients with MGMT-methylated glioblastoma. However, whether this association persists in patients treated with intensified first-line radiochemotherapy according to the CeTeG/NOA-09 regimen remains unclear. We aimed to validate the prognostic impact of ABO blood group in an independent cohort of patients with MGMT-methylated, IDH-wildtype glioblastoma uniformly treated with CCNU/temozolomide (CCNU/TMZ). METHODS: We performed a retrospective single-center cohort study including adult patients with newly diagnosed MGMT-methylated, IDH-wildtype glioblastoma treated according to the CeTeG/NOA-09 protocol between 2008 and 2023. Progression-free survival (PFS) and overall survival (OS) were analyzed using Kaplan-Meier estimates, log-rank tests, and multivariable Cox proportional hazards models adjusted for age, extent of resection, and Karnofsky Performance Status. RESULTS: Sixty-one patients were included, of whom 24 (39.3%) had blood group O and 37 (60.7%) had non-O blood groups. Blood group O was associated with longer OS (median 42.1 vs. 23.7 months; log-rank p = 0.04) and a trend toward longer PFS (median 21.8 vs. 17.5 months; log-rank p = 0.10). After multivariable adjustment, non-O blood groups remained independently associated with shorter PFS (HR 1.86, 95% CI 1.04-3.34; p = 0.037) and OS (HR 2.29, 95% CI 1.16-4.52; p = 0.017). CONCLUSION: Blood group O remained associated with improved progression-free and overall survival in patients with MGMT-methylated, IDH-wildtype glioblastoma treated according to the CeTeG/NOA-09 regimen. These findings support an association between blood group O and improved survival outcomes and warrant further investigation of its biological and clinical relevance in glioblastoma.