Malignant brain tumour (brain cancer)

The skull is a closed box of fixed volume, and anything extra growing inside it sooner or later gets in the way. Hence the peculiarity of brain tumours: they are dangerous not only because they grow, but because of where they grow, and their first complaints rarely look like cancer. A person comes not with weight loss but with an unfamiliar headache in the mornings, with a seizure that has never happened before, or because the family says he is no longer the same man. Such complaints are worth investigating even though something else is usually behind them.

Primary tumours and secondaries are not the same thing

A primary tumour grows from the brain's own cells or from its coverings. In adults these are most often gliomas, tumours of the supporting cells of nervous tissue, the most aggressive of them being glioblastoma; in children, tumours of the cerebellum and the back of the skull predominate. Secondary tumours are commoner than primary ones: they arrive through the bloodstream from the lung, the breast, the skin in melanoma, the kidney or the bowel, and sometimes they are what first announces the disease.

The word malignant means something slightly different here than in other organs. Such a tumour grows into the surrounding tissue instead of pushing it aside, so it cannot be shelled out whole and tends to come back in the same place, but it almost never leaves the skull. Tumours are graded from one to four. Even so, a benign tumour in an awkward place, next to the brainstem or across the drainage paths of the fluid, can be more dangerous than a malignant one at the periphery: a single word in the report is not enough, what count are size, site and speed of growth.

How it usually begins

The complaints come from two mechanisms. The first is rising pressure inside the skull. It causes a headache that was not there before, or that has changed in character: worse in the morning and after lying down for a long time, worse on coughing, straining and bending forwards, sometimes waking the person at night. It builds up over weeks rather than coming and going for years. Nausea joins in, and vomiting may come suddenly, without nausea beforehand, giving brief relief.

The second mechanism is irritation of one particular part of the brain. Hence a first-ever seizure in adult life: this is one of the weightiest signs, even if the seizure was short and everything passed quickly. Hence, too, visual disturbance that keeps increasing: blurring, brief greying of vision on standing up, double vision, loss of part of the visual field that is not noticed at first because the brain fills the picture in. Each of these symptoms on its own far more often speaks of migraine or high blood pressure; what is worrying is several of them together and the fact that month by month they get worse.

Signs that depend on where the tumour sits

From what exactly has changed, the affected area can be guessed before any scan. The frontal lobes govern initiative, planning and self-control: a tumour here shows itself as apathy and indifference to things that used to matter or, on the contrary, as uncharacteristic sharpness. Relatives describe it as becoming a different person. The temporal lobe deals with speech, memory and recognition: the person stops understanding what is said, loses words, has brief episodes of feeling that this has all happened before, or smells something that is not there.

The parietal lobe handles sensation and orientation in space: one half of the body goes numb, left and right get confused; the occipital lobe handles sight, and the same patches drop out of the field in both eyes. The cerebellum gives movement its precision: the walk becomes unsteady, the hand misses the cup, handwriting sprawls. In the brainstem even a small lesion causes double vision, a lopsided face, a nasal voice and choking on food. Tumours in the region of the pituitary give neither pain nor weakness for a long time but upset the hormones: periods stop, milk appears outside breastfeeding, the hands and the features of the face grow coarser, an unquenchable thirst sets in. Loss of the visual field at the sides is also typical of them, so that the person bumps into door frames and does not see a car coming from one side.

When urgent help is needed

Call an ambulance (in European countries, on the single number 112) if:

• a seizure is the first one ever, lasts longer than five minutes, repeats without the person coming round in between, or the person is injured during it;
• a headache came on suddenly and reached its peak within seconds, which calls for a bleed to be ruled out at once;
• the person has lost consciousness and does not wake, is struggling to breathe, or the breathing has become irregular;
• drowsiness and confusion increase over hours, particularly together with vomiting;
• the arm and leg on one side suddenly become weak, the face droops or speech is lost.

See a doctor without delay if a headache has become constant and does not settle with the usual painkillers, wakes you at night or is clearly worse in the first hours after waking; if nausea lasts several days for no clear reason; if sight, walking, speech or handwriting change little by little; if those around you notice a change in character and memory that you cannot see in yourself.

What raises the risk and what does not

The cause of a particular brain tumour usually cannot be named, and that is an honest answer rather than an evasion. Only a few factors have a proven influence: age, since most malignant brain tumours occur in the second half of life, although some types belong to childhood; previous irradiation of the head, for instance radiotherapy for another tumour in childhood; and rare inherited syndromes such as neurofibromatosis type 1 and type 2, tuberous sclerosis, Li-Fraumeni syndrome and Lynch syndrome. Severe suppression of the immune system raises the risk of lymphoma of the central nervous system.

What is not on the list matters just as much. Mobile phones, microwave ovens, power lines, hair dye, an old head injury and stress have been studied many times and have shown no link with brain tumours. Nor is there any direct prevention: no diet and no exercise reduce the chance of a glioma. One qualification is fair: secondary tumours in the brain come mostly from the lung, and the commonest cause of lung cancer is smoking, so giving up cigarettes lowers the risk by that particular route. Healthy habits should not be mistaken for protection against a primary tumour.

How the diagnosis is made

The main test is magnetic resonance imaging with contrast. It shows the lesion itself, its edges, the swelling around it and any shift of neighbouring structures, and from the way the contrast is taken up it allows the nature of the tumour to be guessed. Computed tomography is used in emergencies and when a bleed has to be excluded: it is faster, but it misses small tumours. A plain skull X-ray is useless for this task, since it shows bone rather than brain.

At the appointment the doctor looks at the back of the eye, because a swollen optic disc points directly to raised pressure inside the skull; checks power, coordination, visual fields and speech; and asks how sleep, character and capacity for work have changed over recent months, which somebody close to the patient will describe more accurately.

If a secondary tumour is suspected, the original one is looked for: imaging of the chest and abdomen, examination of the skin, assessment of the breasts. The final answer comes from examining the tissue, either by biopsy or from the material removed at operation. Not only the structure of the cells is looked at but also their molecular features, on which both the choice of treatment and the outlook depend, which is why that report takes longer than usual. A lumbar puncture is not always done: with raised pressure inside the skull it is dangerous.

How it is treated

The plan is drawn up by a team: neurosurgeon, oncologist, radiotherapist, radiologist and pathologist. Surgery usually comes first, and its aim is to remove as much as possible without touching the areas of speech and movement. Operations next to the speech areas are sometimes carried out with the patient awake, so that speech can be checked as the surgery goes on. If the tumour sits where removing it would be dangerous, only a biopsy is taken.

Radiotherapy is given from outside, as a course of short sessions; for small lesions a targeted high dose is used in one or a few sessions. Chemotherapy is limited by the fact that not every drug crosses the barrier between blood and brain; alkylating agents are used most often, some of them as tablets, sometimes alongside radiotherapy. In certain tumours with particular molecular changes, targeted drugs are used.

Part of the treatment is aimed not at the tumour but at the symptoms, and it improves how a person feels a great deal: corticosteroids reduce the swelling around the tumour and within days bring back clarity of thought, anti-epileptic drugs prevent seizures, and if the fluid is not draining a shunt is placed. Doses are set by the doctor and then reduced gradually, and must not be changed on your own.

Life during and after treatment

Tiredness is the commonest and the most underestimated part of recovery. After radiotherapy it may go on increasing for some weeks after the course ends and last for months; it is not a sign that the disease is returning. What helps is not gritting your teeth but spreading your strength: a short rest during the day and some activity every day. Many are troubled more by something else: memory, arithmetic, speed of thought, finding words. A neuropsychologist and a speech therapist work on this, and it is better to start early. If there have been seizures, restrictions on driving and on working with moving machinery have to be taken into account: the rules and the intervals differ from country to country, so check them with your own doctor.

Follow-up is built around repeat scans on a set timetable, but it is worth getting in touch straight away, without waiting for the next date, if the old headache returns, new seizures appear or those around you notice changes in behaviour. Sometimes the tumour cannot be cured. That does not mean there will be no treatment: the aim shifts to holding the growth back, controlling pain, seizures and swelling, and keeping the person independent for as long as possible. This is the work of the palliative care team, and it is better to involve them early, because then they can do more.

Online consultation

A remote appointment fits the first step well, when there are symptoms that worry you and it is unclear what to do about them. The doctor will ask how the headache has been changing, at what time of day it is worse, what makes it worse, what has happened to sight, sleep and memory, will go through the medicines you take and will decide whether a scan is needed and how urgently. Often it turns out to be migraine, overuse of painkillers or high blood pressure, and then no further tests are required.

An imaging report you already have is also easy to go through online: what the words in it mean, how a primary tumour differs from a secondary one, what to ask the neurosurgeon. If treatment is already under way, side effects, the plan for reducing steroids, tiredness and the schedule of follow-up can all be discussed remotely. But with a sudden severe headache, a seizure or confusion there is no waiting for an online appointment: that calls for an ambulance.

This material is for information only and does not replace medical advice.