The most accurate way to determine what type of tumour a child has is to perform a biopsy. A biopsy is a procedure to remove a very small amount of the tumour to be examined by a pathologist under a microscope.
Types of brain tumour biopsies
- The surgeon makes a small hole in the skull and using the scans and a surgical navigation system guides a needle to the tumour to get a biopsy or biopsies. These are typically the size of grains of rice.
- Click here to see an image of a typical biopsy needle and sample.
- Your child may need to have an open biopsy if there is felt to be a high risk of bleeding at a particular site or if a larger sample is required. The surgeon removes some of the skull for easier access to the tumour and takes the samples under direct vision.
- The biopsy is taken as an early part of the operation to remove the tumour and the immediate results phoned back to help the surgeons decide what to do.
Why might my child have a biopsy?
Having a biopsy will provide an accurate diagnosis. With advances in the biology of cancer, the results of the biopsy can also help map out the best treatment pathway for your child. The tumour tissue will be examined by a neuropathologist. They determine the exact type of tumour and how quickly it is growing (its “grade”) and will often now arrange molecular test on the tumour samples to learn more about what treatments it is most likely to respond to. They will play a key role in the multidisciplinary team (MDT) meeting about what the options are for your child’s treatment. Initial results of a biopsy will be available within a few days, but some of the detailed molecular tests can take a week or two.
Not all children need to have a biopsy. Sometimes it might be safest to take as much of the tumour out as possible anyway and then the diagnosis of tumour type will be given after the tumour has been removed. Alternatively, some tumours might be in a location where it is difficult or risky to biopsy or remove them, and it may be decided to monitor them with a follow up scan in the first instance.
Preparing for a biopsy
You will meet the surgical team and neurosurgeon before the biopsy, and they will go through the procedure, risks and benefits. This is a good time to ask all your questions.
Your child will have a CT or MRI scan before the biopsy. Your child will most likely been given a general anaesthetic to fall asleep for the biopsy.
Surgery will usually last between 30 minutes and two hours.