Norwegian Registry of Brain and Spinal cord tumours

Summary from the annual report 2025

Background

This is the fourth annual report from the Norwegian Brain and Spinal Cord Tumour Clinical Registry.The establishment of the registry is a collaboration between the Cancer Registry of Norway and the Norwegian Brain Tumour Consortium (NBTC), and it has been funded by the Norwegian Cancer Society and the Norwegian Brain Tumour Association. The aim of the registry is to improve the diagnosis and treatment of patients with brain and spinal cord tumours.

Method

The Norwegian Brain and Spinal Cord Tumour Registry include adult patients (≥18 years) diagnosed with primary tumours of the central nervous system. Patients with metastases to the brain, and certain tumour types (e.g. melanomas, lymphomasandselect soft tissue tumours) are excluded as they belong to other tumour groups.

From 2024 onwards, diagnosis codes from the Norwegian Patient Registry (NPR) have been included in the calculation of the incidence. Benign tumours are not uncommonly diagnosed solely based on imaging, withouth istological verification. For these patients, it is necessary to obtain additional information from the NPR due to the low coverage of the diagnostic report to the Cancer Registry of Norway. In 2025, a total of 1,897 patients with primary brain or spinal cord tumours were registered. Of these, 596 cases were identified exclusively through diagnosis codes in the NPR.

Classification of diffuse gliomas in this report follows the 2021 WHO Classification of Tumours of the Central Nervous System. The Cancer Registry of Norway adopted the WHO classification in 2023. Several of the analyses in the report include cases registered in the Cancer Registry of Norway prior to, as well as after the adoption of the new WHOclassification. Therefore, when reading the results presented in this report, one must also consider the comments provided in the text.

Analyses in the report are primarily presented by patients’ region of residence, operating hospital, or radiotherapy unit.

Results

The number of registered cases in 2025 (n = 1,897) was lower than in 2024 (n = 2,252). This reduction is largely explained by extensive retrospective registration of diagnostic reports, which has shifted the recorded year of diagnosis backwards in time and reduced the number of cases identified solely through NPR codes. This does not reflect a true decrease in disease incidence.

The average annual incidence in the period 2021–2025 was 21.7 per 100,000 inhabitants for tumours of the brain, spinal cord, and spinal canal, 15.2 for tumours of the meninges, and 12.1 for tumours of the pituitary gland and related structures. Regional differences in incidence were small and are mainly attributed to variations in reporting rather than true differences in disease occurrence. National 30-day postoperative mortality in the period 2024–2025 was 0.7% following resection of an intracranial tumour, while it was considerably higher following diagnostic biopsy (8.0%). The increased mortality after biopsy is largely considered to reflect selection of older and frailer patients and underscores the need for a restrictive use of biopsy in cases where tumour-directed treatment is not planned.

In 2024, the advisory board established four process quality indicators with target levels. For the 2025 annual report, the indicators were further developed and the criteria for two of them were adjusted. At the national level in 2025, target achievement was moderate for two indicators and low for two.

• The proportion of patients with the first surgical intervention for diffuse glioma grade 4 who received additional oncology treatment.

Eighty-eight per cent of patients with diffuse glioma grade 4 received further oncological treatment following surgical intervention, corresponding to moderate target achievement (target ≥90%).

• The proportion of patients with diffuse glioma grade 4, diffuse glioma grade 2–3, non-diffuse glioma, and intracranial meningioma who received postoperative MRI within 72 hours.

Ninety-three per cent of patients undergoing resection of glioma or intracranial meningioma received postoperative MRI within 72 hours, also corresponding to moderate target achievement (target ≥95%).

• The proportion of patients who started radiotherapy within 28 days of surgery for glioblastoma.

Sixty‐one per cent of patients under 70 years of age with glioblastoma started radiotherapy within 28 days of surgery, which represents low target achievement.

• The proportion of MGMT results recived within 14 days fromsurgical for glioblastoma.

Thecriterion for timely MGMT promoter methylation analysis was changed from median turnaround time to the proportion of analyses reported within 14 days. Although no hospital yet met the target level of ≥85%, the median turnaround time improved from 20 days in 2024 to 15 days in 2025.

Diffuse glioma grade 4 accounted for 263 patients in 2025, of whom 93.5% were diagnosed with glioblastoma. Median overall survival for glioblastoma in the period 2021–2025 was 12months. Regional variation insurvival was observed, with lower median survival in the Northern Norway Health Region. Analyses indicate that this is largely associated with a higher proportion of diagnostic biopsies in patients over 70 years of age and a lower proportion receiving further oncological treatment. These findings have been followed up with regional quality improvement initiatives.

In 2025, 55 patients were diagnosed with histologically verified diffuse glioma grade 2–3. Five‐year relative survival varied substantially between subgroups, from 96.8 % for oligodendroglioma WHO grade 2 to 68.0 % for astrocytoma WHO grade 3. Small numbers limit the possibilities for reliable analyses of regional variation.

Five‐year relative survival for patients with benign meningioma was very high, approaching or exceeding 100%, while malignant meningioma was rare and associated with a markedly poorer prognosis with a five‐year relative survival of 33.8%. The number of meningioma surgeries per 100,000 inhabitants was relatively similar across regions, whereas the use of radiotherapy showed greater variation.

A total of 450 patients were registered with a pituitary tumour in 2025, of whom 22 % underwent surgical treatment. For this tumour group the data remain affected by lowcoverage of clinical diagnostic reports, and incidence figures must therefore be interpreted with caution.

Assessment of data quality and further development of the registry

In 2025, coverage was 59.4% for diagnostic reports and 70.1% for surgical reports. Although this represents an improvement compared to previous years, low coverage remains a key methodological challenge. Continued efforts to increase reporting are essential to strengthen the analytical basis of future reports.

In 2025, 76 patients with neuro-oncological disease were included in clinical interventional studies. The Norwegian Brain Tumour Consortium aims to increase inclusion in such studies, and the registry intends to incorporate analyses of this activity in future reports.

Preparations for the collection of patient-reported outcome measures (PROMs) and patient-reported experience measures (PREMs) have been completed, and data collection is planned to begin in spring 2026. These measures are considered important for documenting patients’ experiences of the quality of health care services.