Tumors of the central nervous system

In Norway, approximately 1,000 new primary tumors are diagnosed annually in the brain, spinal cord, meninges, cranial nerves or pituitary gland, accounting for about 3% of all cancers.
Last updated:

Tumors of the central nervous system are a heterogeneous group. These may have very different origins and prognosis and therefore require different treatment.

Tumor arising in the central nervous system is called primary. Primary tumors can occur in the brain, spinal cord, meninges, cranial nerves or in the pituitary gland. These tumors rarely spread to organs outside the central nervous system.

If the tumor has arisen elsewhere in the body and has spread to the central nervous system, it is called secondary, daughter tumor or metastasis. For example, lung cancer, breast cancer, kidney cancer, melanoma and bowel cancer can spread to the brain. Somewhere between 10% and 30% of patients with cancer outside the central nervous system have metastasis to the brain.

Source: kreftlex.no

Risk factors

The cause of brain tumour development is unknown in 95% of cases.

A causal association between environmental factors and primary brain tumour development has not been definitively demonstrated. However, ionising radiation may predispose to later development of some types of brain tumours. It is therefore important that radiological examinations based on ionising radiation are performed according to a thorough position of indication. 

Factors that may increase the risk are X-rays, radiotherapy, CT scans and other radiation from radioactive substances. That's especially true for those who have had treatments and scans for childhood cancer. However, X-rays and CT scans are very important for diagnosing disease so that you receive proper treatment. 

Environmental factors such as alcohol and tobacco are known carcinogens, although no direct link between these and brain tumour development has been demonstrated.

Other cancers and earlier treatment for cancer may increase the risk.

Some diseases can cause a reduced immune system, including HIV and AIDS.

There is no definite association between long-term use of mobile phones and the development of glioma, meningioma and vestibular schwannoma.

Heredity exists in some cases, but this is rather the exception than the rule. Certain genetic conditions may predispose to the development of brain tumor. However, a very small proportion of patients with brain tumours have such a genetic condition.

Read more about the causes of central nervous system cancer on kreftforeningen.no

Read more about risk factors in the National action programme with guidelines for diagnosis, treatment and follow-up of brain tumours

silhuett gruppe.png

New cases

456 men and 532 women developed a central nervous system tumor in Norge in 2022. The number of cases per 100,000 people is 16.0 for men and 17.8 for women.

Aging

The median age for tumours of the central nervous system is 61 years for both sexes, i.e. half of all those diagnosed are over 61 years of age.

The risk of getting a tumor in the central nervous system increases with increasing age, reaching a peak around the age of 70. 

Survival

Five-year relative survival in 2021 is 74.5 per cent for women and 57.0 per cent for men. 

The figure shows relative survival up to 15 years after diagnosis, distributed by age in the period 2017-2021. From Fig. 8.1-T in Cancer in Norway 2021.

Survivors with a tumor of the central nervous system

The number of people who have or have had cancer of the central nervous system as of 31.12.2022 is 15,270 people. 8,790 of these were diagnosed more than 10 years ago.

Number of deaths

In 2021, 222 men and 211 women died as a result of a tumor in the central nervous system.

Development over time

Trends in incidence (dark blue), mortality (light blue) and 5-year relative survival (green) of central nervous system tumours in the period 1965-2022. From figure 9.1-T in Cancer in Norway 2022

Trends in incidence (red), mortality (pink) and 5-year relative survival (brown) of central nervous system tumours in the period 1965-2022. From figure 9.1-T in Cancer in Norway 2022

The frequency of tumors in the central nervous system increased steadily until about 2007, after which a levelling off and possible decline are seen. The reason for the decline is uncertain, but may be due to improved diagnostic equipment and X-rays have captured and reduced the reservoir of most benign and less malignant tumours in the population, so that the number of people who are diagnosed with this is now lower than previously.

The number of the most malignant and hot-tempered tumors is relatively stable. The survival of central nervous system tumours has been relatively stable over the past 20 years.

artikler m statistikk.png

Quality registry for brain and spinal cord tumours

The work to establish a quality registry for brain tumours in the Cancer Registry of Norway started in 2021/2022. The Cancer Registry received funding from the Norwegian Cancer Society in 2021. These funds come from the fundraiser Krafttak against cancer, which in the years 2019-2021 had cancers with low survival as its purpose. The Norwegian Cancer Society appointed a national expert group for brain cancer research, of which the Cancer Registry of Norway, represented by Tom Børge Johannesen, is a part. Several members of the expert group participate actively in the advisory board of the Quality Registry for Brain Tumours.

The Quality Registry for Brain and Spinal Cord Tumors will publish its first annual report in 2023 with results from 2022. From 2024, the report will include more detailed analyses. The more detailed analyses will be based on data reported to the Cancer Registry of Norway from treating hospitals and from biopsy/surgical specimens received by the Cancer Registry. From 2023 onwards, reporting and registration will be more detailed than in previous years.

The quality registry for brain tumours does not currently have national status, but the funds from the Norwegian Cancer Society ensure operation of the registry for 3 years.  

Examples of results from the Prostate Registry's annual report 2022(Norwegian only):

Proportion of patients with diffuse high-grade glioma receiving postoperative radiotherapy within three months of surgical intervention (biopsy and/or resection), by region of residence, 2019–2022. From Fig. 3.10 of the annual report (Norwegian only).

After a biopsy or resection of diffuse high-grade glioma, the guidelines recommend radiation therapy. The figure shows that the proportion receiving radiotherapy is high and that the median number of days to start treatment is about four weeks for all regions.

The challenges we have had in distinguishing between primary and recurrence surgery may affect the proportion who receive radiotherapy. Furthermore, the boundary between diffuse low-grade glioma and diffuse high-grade glioma is a recurring challenge throughout this report.

Regional differences in the proportion of patients with diffuse high-grade glioma who undergo radiotherapy must therefore be interpreted with caution

Questions about cancer

The Cancer Registry of Norway is a research institution. Our professionals therefore do not answer questions about diagnosis, assessment, treatment and follow-up from patients or their relatives.

Questions about this should be directed to your own GP, treating institution or the Cancer Society Advisory Service tel: 21 49 49 21

Useful Links

Read about brain tumor in adults on helsenorge.no

Read about a brain tumor in adults on kreftforeningen.no

Brain Tumor Association

National action programme with guidelines for diagnosis, treatment and follow-up of patients with brain tumours

Brain Tumors information on the National Cancer Institute website