The purpose of this post-authorisation medical device study is to obtain real life data on the use of tumor-treating fields (TTFields) in patients with newly diagnosed GBM in routine clinical care in Germany. Patients with newly diagnosed GBM and clinical indication for TTFields treatment will be enrolled in the study after signing Informed consent to use their data and process it centrally for research purposes. The clinical indication for TTFields is one of the inclusion criteria and is defined prior to inclusion by the treating physician. The patient's decision regarding TTFields treatment is part of the observation and will be assessed within the baseline visit.

Glioblastoma (GBM) is the most common malignant primary tumor of the brain. The current standard of care for patients with newly diagnosed GBM consists of maximal surgical resection, approx. 60 Gy of radiotherapy together with chemotherapy using temozolomide (TMZ), followed by maintenance TMZ for 6 months. This treatment scheme was shown to extend median survival from 12.1 to 14.6 months compared to surgery and radiotherapy alone. This survival was essentially unchanged since 2005 despite numerous clinical Phase 3 trials conducted.

Although immense efforts were made over the years with different treatment strategies, the survival of patients with newly diagnosed GBM remained very poor until recently. Tumor-treating fields (TTFields) are low-intensity, intermediate frequency, alternating electric fields delivered continuously through adhesive patches, called transducer arrays, to the area of the brain where the GBM tumor is located and help slow down or stop glioblastoma cancer cells from dividing. These transducer arrays are applied to the scalp and are connected to the wearable and portable device.

TTFields are the first treatment since 2005 to demonstrate significantly extended median overall survival and significantly improved long-term survival (one to five year survival rates) compared to the current standard of care. In addition, TTFields significantly extended progression-free survival.

In the Phase 3 trial in newly diagnosed GBM (trial EF-14) the results demonstrated that the addition of TTFields to maintenance TMZ significantly extends both, median and long term survival, as well as progression free survival of patients with newly diagnosed GBM. The magnitude of survival benefit seen is even better to that seen for addition of TMZ to radiation, which established TMZ as the standard of care for 1st line GBM treatment in 2005. Quality of life (QoL) was maintained with the use of TTFields + TMZ in patients for whom 12 months of QoL data were available. The addition of TTFields to TMZ therapy in patients with newly diagnosed glioblastoma was not associated with any significant increase in systemic toxic effects compared with TMZ therapy alone. The most commonly reported side effect from the delivery of TTFields was a mild-to-moderate skin irritation beneath the transducer arrays.

Inclusion Criteria:

• Newly diagnosed histologically confirmed GBM (WHO-Grade IV)
• Patient within first 3 cycles of first-line tumor-specific maintenance chemotherapy
• ≥ 18 years of age
• Clinical indication for TTFields treatment
• Given informed consent for use and processing of data

Exclusion Criteria:

• Present or planned pregnancy
• Significant additional neurological disease (e.g. significantly increased intracerebral pressure (ICP) with a significant midline shift of the brain)
• Active implanted medical device (e.g. deep brain stimulator)
• Documented allergy to conductive hydrogel
• Skull defect (e.g. missing bone with no replacement, bullet fragments in the skull)

Patients with newly diagnosed GBM with clinical indication for TTFields treatment, as indicated by the treating physician, will be included in the study, provided all inclusion and no exclusion criteria are met and written consent is given to use and process their routine clinical data according to data privacy standards.