Brain and spinal tumours

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Grades of brain and spinal cord cancer

Grading is a way of classifying brain and spinal cord cancer cells based on their appearance and behaviour when viewed under a microscope. To find out the grade of a tumour, the biopsy sample is examined under a microscope. A grade is given based on how the cancer cells look and behave compared with normal cells (differentiation). This can give the healthcare team an idea of how quickly the cancer may be growing and how likely it is to spread.

The World Health Organization (WHO) grading system is used for classifying brain and spinal cord cancer.

  • Tumours may contain several grades of cells. The highest, or most malignant grade, determines the grade of the tumour, even if most of the tumour is a lower grade.
  • Tumours do not always stay the same. If a tumour undergoes a transformation, the name and grade of the tumour might change.
    • A low-grade (benign) tumour might become high-grade (malignant).
    • A low-grade tumour might come back (recur) as a high-grade tumour.

WHO classification for central nervous system cancers
WHO gradeExplanation


low-grade tumour

cells grow very slowly

cells look almost normal under a microscope

rarely recurs if completely removed

rarely spreads to nearby tissue

least malignant type of brain or spinal cord tumour


low-grade tumour

cells are relatively slow growing

cells look slightly abnormal under a microscope

tumour can grow into surrounding tissues

tumour may recur after being removed

can recur as a higher-grade tumour


high-grade tumour

cells grow at a faster rate

cells look abnormal under a microscope

tumour is growing into surrounding tissues

tumour tends to recur, often at a higher-grade


high-grade tumour

cells grow rapidly

cells look very abnormal under a microscope

tumour grows new blood vessels to maintain rapid growth

tumour grows deeply into the surrounding tissues

areas of dead cells may be present in the centre of the tumour

most aggressive and malignant type of brain or spinal tumour

Grading plays an important part in planning brain and spinal cord cancer treatment and can also be used to help estimate the prognosis (future outcome).


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