Brain tumour and meningioma

There are few sentences more frightening than "something has shown up on the scan". And there are few moments when good information is worth more, because days usually pass between the scan and the appointment with the specialist, and those days fill up on their own with the worst of what you find while searching.

So the figure that belongs first is this one: of every hundred primary brain tumours, seventy-four are not malignant.

What it actually is

"Brain tumour" is a label that covers very different things, and on its own it tells you almost nothing. There are three broad families.

The ones that arise from the coverings of the brain. The meningioma is the most common of all brain tumours in adults. It grows from the meninges, the membranes that wrap around the brain, and in the great majority of cases it is benign: it does not invade brain tissue, it displaces it. It grows slowly, sometimes over decades.

The ones that arise from brain tissue itself. These are the gliomas, and the range here is enormous, from very slow-growing tumours to glioblastoma, which is aggressive. These do infiltrate the brain, and that is the reason surgery alone is almost never enough.

The ones that came from somewhere else. Metastases: a tumour of the lung, the breast, the kidney or the skin that has reached the brain through the bloodstream. In sheer numbers these are the most common brain tumours of all.

Which of the three it is changes everything: the treatment, the outlook and the urgency. And what decides which it is is not the MRI but the analysis of the tissue. That is why what gets proposed first is sometimes a biopsy rather than major surgery.

How it shows up

Many cause no symptoms at all and turn up by chance, on a scan ordered for something else. In the general population, brain MRI finds a benign tumour — almost always a meningioma — in 1.6 per cent of people.

When they do cause symptoms, these tend to be of three kinds: the ones that come from taking up space (headache that appears in the early hours or on bending forwards, nausea, vomiting), the ones that come from irritating the cortex (a seizure, sometimes the first of a person's life) and the ones that come from affecting a specific function (weakness down one side, difficulty speaking, loss of part of the visual field, changes in personality that the family notices before the patient does).

It is worth being clear about headache, because it is what brings most people here searching for this page: headache on its own, with no other neurological sign, is a very poor predictor of a brain tumour. Headaches are extraordinarily common; tumours are not.

The numbers worth having

From the central nervous system tumour registry of the United States, which covers practically the whole population of the country:

• 74 per cent of primary brain tumours are not malignant.
• Five-year relative survival for the non-malignant ones: 91.7 per cent. For the malignant ones: 34.8 per cent.
• In adults over forty, the most common tumour is the meningioma.
• Of everyone alive today with a diagnosed brain tumour, only 14 per cent has a malignant one.

On the meningioma found by chance, there is a study that followed 62 patients with incidental meningiomas for up to twelve years, and the result is worth reading twice:

• In more than 40 per cent of cases nothing had to be done. Monitoring them was enough.
• In 63 per cent, the growth was self-limiting: they grew a little and then stopped.
• None developed symptoms before a decision to intervene was taken.
• Nineteen patients died during follow-up, of causes unrelated to the tumour. Two died of the meningioma.

And on glioblastoma, the one most searched for and the one with the worst outlook, honesty requires saying it: observed median survival is around eight months, and that has not changed substantially in years. It is exactly for that reason that promises of alternative cures for glioblastoma are especially damaging.

What you will hear that is not true

"A meningioma is cancer." It is the number one search on the subject and the answer is no, in the great majority of cases. The typical meningioma is benign: it grows slowly, it does not invade the brain and it does not spread.

"A benign tumour can turn malignant." It is exceptional. In the cohort with twelve years of follow-up, two patients out of sixty-two died of a grade 2 meningioma. Transformation exists but it is rare, and it is precisely one of the things being looked for at follow-up.

"Every meningioma has to come out." More than 40 per cent of the incidental ones never needed treatment. A small tumour, causing no symptoms, in a place where it does no harm, in an older person, is very often monitored and nothing more. Active surveillance is not doing nothing: it is a medical decision with scheduled follow-up.

"Mobile phones cause brain tumours." It is the most persistent myth and also the best studied. A prospective cohort of 264,574 people, followed for more than seven years, found no increase in risk: for every hundred cumulative hours of calls, the relative risk was 1.00 for glioma and 1.01 for meningioma. Nor was there any in those who had used a phone for more than fifteen years. The World Health Organization review reaches the same conclusion.

"I have a headache, it must be a tumour." Headache with no other neurological sign is a poor predictor. If this worry is taking up more of your thinking than it should, that is a legitimate reason to be seen in itself, and it is better settled by an examination than by more searching.

Diets, fasting and alternative therapies for glioblastoma. There is no evidence behind them, and the cost of pursuing them is not only financial: it is time, in an illness where time is what there is.

What will happen at the appointment

The MRI will be looked at with you, and it is worth doing it that way: the location, the size, whether it takes up contrast, whether there is swelling around it. Often the images alone are enough to say with reasonable confidence which family it belongs to.

Then you will be examined, including your visual fields and the back of your eyes. And one of three courses will be put to you: monitoring with an MRI in a few months, a biopsy to find out what it is, or surgery. All three are valid answers depending on the case, and the first is far more common than people imagine.

If the tumour is malignant or uncertain, the case should be discussed at a meeting with oncology, radiotherapy and pathology. It is reasonable to ask whether that is going to happen.

Questions worth writing down before you go

• From what the images show, which type of tumour is most likely?
• Is monitoring reasonable instead of operating? How often, and for how long?
• If surgery is needed, is the aim to remove all of it or as much as can be removed safely?
• Which specific function is at risk because of where it sits?
• Will my case be discussed at a tumour board?
• If it is malignant, what comes after the surgery?

The questions people ask most