Brain tumours are not easy to understand.

Except for certain genetic conditions and for some children exposed to radiotherapy on their brains, e.g. in cases of leukaemia, we do not know what causes tumours, in some cases we do not know what causes them to grow and ultimately our management of brain tumours is based on several basic principles: a) is the tumour posing an immediate risk to the patients life? b) is the tumour posing a soon to be significant risk to the patients functioning and causing significant symptoms which might then pose a risk in future to their life? c) is the tumour posing a risk to the patients functioning and causing symptoms which might not pose a risk in future to their life? d) is the tumour posing a potential risk to the patients functioning and causing symptoms which might not pose a risk in future to their life? e) the tumour is not posing a risk to the patients functioning and is not the cause of their symptoms. 

Naturally, it is more complicated than that.

I created the above categories to help people understand. The majority of brain tumours exist in categories A, B and E. The first requires an immediate emergency operation, e.g. rare cases of a patient arriving in A&E in a coma and on CT a brain tumour causing significant compression of the brain is detected. The second requires semi-urgent clinical assessment, patient discussion and consent and an operation inside several weeks, e.g. a patient having significant headache, limb weakness, balance and speech issues. The third requires thorough patient discussion and counselling about the tumour, reassurance and repeat imaging at appropriate intervals to check for growth which can then dictate management options in a routine elective manner. The categories of C and D have a lot of nuance, require multiple discussions amongst colleagues prior to operating.

In summary in neurosurgery one should only operate if necessary.

This is because every single operation has risk. So if a patient has headache and the MRI demonstrates a highly aggressive incurable tumour, e.g. a glioblastoma, they need urgent clinical assessment, thorough patient counselling and discussion of all options (as glioblastomas have a median life expectancy of 11-months despite surgical and oncological treatment). But complications can do and occur even though the intention is to treat this aggressive disease to give that patient more time. Therefore, if a patient has a headache and the MRI demonstrates a small benign meningioma it needs to be made carefully clear that the tumour is not causing their symptoms, does not require an operation and will be managed by MRIs at specific intervals to check for growth. 

Why?

Because operating on a brain is extremely high risk and it should not be undertaken lightly. The two commonest tumours are glioblastomas and meningiomas. The former are highly aggressive intrinsic tumours that despite advances in surgical technique and oncological treatments dramatically shorten life expectancy. The latter are usually benign slow growing tumours but if very large and compressing brain require an operation. However, they have a propensity to cause significant haemorrhage whilst being resected which can compromise life. So, you have a highly aggressive tumour which can be resected in its entirety but despite this it recurs extremely quickly and no cure exists versus a slow growing benign tumour which if an operation is required can result in a resection which proves extremely costly due to the haemorrhagic potential of the tumour. You do not cross match patients for a glioblastoma resection but you absolutely cross match them for meningiomas. 

Brain tumours are not straightforward.

This is why neurosurgeons trained in Britain stress that only if it is necessary should an operation be done. This is not always easy to understand.