Glioblastoma is the most common and aggressive malignant brain tumor in adults, with a median survival of approximately 15 months despite standard treatment, which includes maximal safe resection followed by chemoradiotherapy with temozolomide. Imaging, especially MRI, plays a key role in diagnosis, treatment planning, and surveillance; however, standardized imaging protocols for post-treatment follow-up remain undefined. Guidelines from major oncology bodies vary, with surveillance intervals ranging from 2 to 6 months. While routine imaging aims to detect early asymptomatic recurrences, emerging evidence questions its survival benefit and highlights concerns about cost, patient anxiety, and potential overtreatment due to misinterpretation of post-treatment changes.

The MAGNOLIA study is a randomized, open-label, Phase III trial comparing standard surveillance imaging to symptom-based imaging for glioblastoma patients post-treatment. Patients will undergo 3-monthly clinical evaluations, with either 6-monthly MRIs (standard arm) or imaging only upon symptom onset (experimental arm). The primary endpoint is 2-year overall survival, with secondary endpoints including progression-free survival, salvage treatment rates, quality of life, and cost-effectiveness.

A total of 240 adult patients with controlled glioblastoma post-standard therapy will be enrolled over 2 years and followed for one additional year. Statistical analysis will use Kaplan-Meier and log-rank tests, with quality of life assessed via EORTC QLQ-C30 and BN20 questionnaires. Ethical oversight, informed consent, and patient confidentiality are prioritized throughout. The study aims to provide evidence-based guidance on imaging strategies, potentially optimizing patient care while reducing unnecessary imaging and associated burdens.