Childhood Brain Cancer Article 2

Classification, Grading and Staging of Cancers


Before we go on to find out about Gliomas, it will be useful to have a look at how cancers are classified in general, as the same rules apply to Childhood Brain Cancers.

In order to work out what kind of treatment is right for any given cancer, the oncologist needs to know three things. These days, some of these questions can be answered before surgery, by using Magnetic Resonance Imaging, (MRI), but most often, brain cancers and spinal cord cancers need to be operated in order to take a sample for the pathologist (biopsy).


1) Classification: What kind of tumour is it? 

In other words, what do its cells look like, and where is the tumour located? For example, brain and spinal cord tumours arise from normal cells in the brain, mostly from the glial cells. A tumour arising from one of these cells is called a glioma (the -oma part of the word means 'cancer') The name 'Glioma' is a very general word, though, and the tumour will be further classified according to its particular characteristics.


2) Grading: How malignant is it?

If it's deemed necessary, and the tumour is able to be operated, a biopsy is taken. The cancer is studied under the microscope, the pathologist checking to see how many dividing tumour cells are present. The tumour is then given a grading from 1-4 according to how agressive it is.

3) Staging: How far has the tumour already spread?

Part of the process of determining how far a cancer has spread can be done before surgery, by looking at the MRI results. From the image, the oncologist can see if there are any other tumours in the area one would expect the particular type of tumour to spread to. For instance, glial tumours generally do not spread beyond the brain and spinal cord, so an MRI of the spinal cord is all that's needed to stage this kind of cancer.

For some tumours, the surrounding area of the tumour and possible places in the body the tumour could have spread to through the lymph system need to be carefully examined in order to work out what the spread of the cancer is. In some cases, a lumbar punch and examination of the spinal fluid can provide information towards staging also.

Source: Classification, Grading and Staging of Pediatric Brain and Spinal Cord Tumours, Peter C. Burger,MD and Kenneth J. Cohen, MD. (written for the Childhood Brain Tumour Foundation, www.childhoodbraintumour.org)