gms | German Medical Science

Objective: Post resection external beam radiation therapy and concomitant temozolomide is the standard of care for patients with newly diagnosed glioblastoma. However, the optimal timing of such therapy is ill-defined and its impact on survival is unknown. In this study, we assessed the influence of the time interval between surgical resection and radiochemotherapy on survival in primary glioblastoma patients.

Methods: We retrospectively reviewed all glioblastoma patients treated at our institution with the goal of maximal safe resection between 2010 and 2015. All patients received treatment according to the EORTC 22981/26981 protocol. Patients were assigned to groups based on the time interval until the begin of radiochemotherapy of up to 27 days (group I), 28-33 days (group II) and 34 days or more (group III). Kaplan-Meier and multivariate Cox regression analyses were used to compare overall survival (OS) and progression-free survival (PFS) between groups stratified by postoperative delay to initiation of radiation treatment.

Results: Our study population included 182 patients. The median time to initiation of radiochemotherapy was 30 days. Median PFS and OS were not influenced by the time interval to initiation of adjuvant treatment (PFS: 8,6 vs 9,2 vs 6,8 and OS: 15,0 vs 17,4 vs 18,2 months for group I to III respectively, p>0,05). On multivariate analysis Karnofsky performance status, age, MGMT promotor methylation status and involvement of midline structures were independent predictors of PFS and OS.

Conclusion: The timing of initiation of concomitant radiochemotherapy does not impact survival after resection of glioblastoma.