Objective: The patient data, along with the diagnoses of glioblastoma multiforme (GBM), the treatments administered, and the clinical outcomes of these treatments, were assessed to inform future therapeutic strategies. Material and Methods: The records of 123 patients diagnosed with GBM, treated at the medical oncology outpatient department of the Atatürk Training and Research Hospital of İzmir Kâtip Çelebi University, Faculty of Medicine between 2007 and 2020, were collected and analyzed. Results: The study found that adjuvant chemoradiotherapy enhanced overall survival (OS). Re-operation and stereotactic radiosurgery offered a survival benefit in patients with recurrent disease, whereas re-irradiation did not. For patients with relapsed disease, re-administration of temozolomide proved beneficial for those with progression- free survival (PFS) over 15 months, and the combination of bevacizumab plus irinotecan (BEV/IRI) was chosen for patients with PFS under 15 months. Patients who underwent second-line chemotherapy exhibited significantly higher OS compared to those who did not. Additionally, patients treated with bevacizumab as a second-line therapy showed significantly greater OS than those who had not received bevacizumab. Regarding PFS and OS, the study's real-life data surpassed that reported in existing literature. Conclusion: Given the high mortality and recurrence rates associated with GBM, the development of new treatment modalities is imperative. Treatment strategies should include combination therapies and should be complemented by supportive care when necessary, always adhering to the principle of “first, do no harm.”