The major types of primary tumour are given in Table 30.1, and the percentages of these tumour types in our own practice are shown in Figure 30.1. The majority of tumours (58%) are gliomas (Figure 30.1). Of the gliomas, two-thirds are glioblastomas (Figure 30.2), making this the most common type of primary CNS tumour in adults. Gliomas in general, and glioblastomas, in particular, are devastating tumours, and therefore consume much of the energy and resources of the neuro-oncology unit. Although gliomas represent the major diagnosis of primary brain tumours, over a third of new referrals are for other tumour types, so appropriate attention also needs to be directed towards those.

Table 30.1 A simplified classification of the major categories of brain tumour

Intrinsic tumours (i.e. those arising within the brain substance)

Glial tumours

Astrocytoma

Lymphoma (primary CNS lymphoma – PCNSL)

Extrinsic tumours of the brain covering

Meningioma

Other tumours

Pituitary adenoma and craniopharyngioma

Acoustic (vestibular) schwannoma

Skull base chordoma and chondrosarcoma

Cerebral metastases

Notes:

1. Glioblastoma used to be known as ‘glioblastoma multiforme’

2. The glial tumours are divided into four grades: grade I and II together constitute low-grade gliomas (LGGs), while grade III and IV tumours together are the high-grade gliomas (HGGs). The term ‘anaplastic’ is equivalent to a grade of III. A grade IV glioma is a GBM.

3. Grade I tumours are rare in adults, though they do occur. They also appear in adult practice in patients treated as children who have outgrown the paediatric services.

4. A large number of other uncommon tumours also occur.

5. Medulloblastoma is predominantly a disease of childhood, but does occasionally occur in adults (i.e. patients over 16).

Figure 30.1 Frequency of the main tumour types in 1300 new adult neuro-oncology referrals. Metastases are few, accounting for only 6% in this specialized neuro-oncology practice.

Figure 30.2 Percentages of different grades of glioma. Grade IV glioma is glioblastoma.

Gliomas are graded according to the World Health Organization (WHO) 2000 classification, on a scale of I to IV, where IV is the most malignant. Grade I and grade II gliomas together are termed low-grade gliomas. Grade I tumours are more typical of childhood but occasionally occur in adults. Grade III and grade IV tumours together constitute high-grade gliomas. Grade III tumours may also be called ‘anaplastic’ and grade IV gliomas are known as ‘glioblastomas’.

Gliomas arise from astrocytes and oligodendrocytes, cells which nourish and support neurons. Primary tumours of neurons alone are extremely uncommon, though they do exist (e.g. neurocytoma). There is a surprising large range of very rare tumours within the brain, but apart from those mentioned explicitly in Table 30.1, and described below, their overall management and outcome can generally be inferred from the grade of the tumour.

The male to female ratio for gliomas is 1.4 to 1. Meningiomas are commoner in females than males, in the ratio of 2:1, which is unusual in oncology. There are only two definite aetiological factors for the development of brain tumours: exposure to ionizing radiation and genetic predisposition. Genetic syndromes include Li-Fraumeni syndrome, neurofibromatosis types 1 and 2, Gorlin’s syndrome and ataxia-telangiectasia. These syndromes may account for 1–2% of brain tumours. They are normally easily identifiable, and many of the cases present in childhood. Other genetic factors may play a part but as yet are ill understood. Mobile phones and electricity power lines have been proposed as predisposing factors, but good evidence exists that these do not influence risk.

Secondary CNS metastases may arise from primary tumours at almost any site. However, certain cancers have a propensity to metastasize to the brain. Lung cancer accounts for 60% of metastases, followed by breast (15%). Other tumours causing metastases include kidney, colon, melanoma, pancreas, and ovary. Metastases are usually multiple but occasionally can be solitary. The majority (85%) develops in the cerebrum.

Anatomy of the CNS

Anatomy is the key to understanding the presentation of neurological tumours, their spread, and concepts about treatment, particularly with radiotherapy and surgery.

Anatomy of the brain

Tissues of the brain

Within the brain substance itself, tissue is divided into grey and white matter. Grey matter covers the surface folds of the brain (gyri), and broadly is the location of active neurons. White matter lies below the gray matter and contains fibres which communicate with other parts of the brain and body, equivalent to electrical cabling. At a cellular level, the brain is composed of both neurons and cells designed to support the structure and function of those neurons, the glial supporting cells. Almost all tumours of the brain substance arise in the glial supporting cells (principally astrocytoma and oligodendroglioma). Primary tumours of neurons are very rare.

The major structures of the brain

Figure 30.3 shows the outside of the brain to explain the nomenclature of the principal lobes. In right-handed patients, the left hemisphere is almost invariably dominant.

Figure 30.3 The major anatomical divisions of the brain.

The frontal lobe is very large, extending back to the central sulcus, which divides it from the parietal lobe. The motor cortex sits immediately in front of the central sulcus. More anteriorly, the frontal lobe is responsible for intellect, motivation and emotional response. Damage to the frontal lobes can affect intellectual performance, including reasoning, memory, the initiation of activity and insight. The medial frontal lobe is particularly important for these activities and damage to both medial frontal lobes is extremely destructive to the intellect. The motor speech centre (Broca’s area) lies in the dominant frontal lobe (see Figure 30.3).

The parietal lobe extends from the central sulcus posteriorly onto the occipital lobe, and is also large. The parietal lobe has large areas which are silent, with no obvious functional activity. Immediately behind the central sulcus is the sensorimotor cortex, which deals predominantly with reception of sensory information. In reality, there are other areas adjacent to both motor and sensory cortices which support those functions.

At the most posterior part of the cerebral hemisphere is the occipital cortex, which deals with central processing of visual information. The optic radiation connects the optic tracts to the occipital cortex, and runs through the temporal and parietal lobes to arrive at its destination. Tumours lying along that pathway can therefore affect vision.

Inferiorly and laterally, with its tip in the middle cranial fossa, lies the temporal lobe. The medial part is involved in short-term memory. In the dominant hemisphere, the temporal lobe is the location for one of the speech centres, the auditory cortex.

The pons and medulla together form the brainstem. These have processing functions, important functional centres such as the respiratory centre, and also carry all motor and sensory information between the cerebral cortex and spinal cord (Figures 30.3 and 30.4). Even small lesions within the brainstem have very severe neurological effects. The function of the cerebellum is the subconscious control of movement. Damage to the cerebellum therefore leads to ataxia and other difficulties with coordinated movement.

Figure 30.4 Normal anatomy of the central nervous system. MR midline sagittal section.

(Courtesy Dr L Turnbull, MRI Unit, Sheffield)

The lobes of the brain communicate by extensive pathways made up of white matter. These run from front to back, side to side, and up and down through the brain. Tumours which spread through white matter tracts (especially the gliomas) therefore have access to pathways which can allow them to spread extensively. The corpus callosum (see Figure 30.4) is the major route of side to side communication between the two cerebral hemispheres. High-grade gliomas lying medially in the hemisphere often involve this structure, which allows spread into the opposite hemisphere.

Functional imaging, especially using magnetic resonance imaging (MRI), has demonstrated that damage to particular areas of the brain, for example the motor cortex, can lead to some function being taken over by other areas, provided that the rate of damage is slow. In the adult, this can occur in only a modest way, but can explain why, in some circumstances, patients do not lose all the neurological function that would be expected.

Anatomy of the cerebrospinal fluid (CSF) pathways and hydrocephalus

The major cerebrospinal fluid (CSF) structures are shown in Figure 30.5. CSF is produced by the choroid plexus within the two lateral ventricles, and flows into the third ventricle anteriorly through the foramen of Munro (Figure 30.5). CSF exits the third ventricle posteriorly through the aqueduct, and flows into the fourth ventricle. From there, CSF leaves the fourth ventricle through three foramina (the foramina of Luschka laterally and the foramen of Magendie in the midline) to surround the outside of the brain. A small amount also passes down the central canal in the spinal cord. CSF is actively absorbed by the arachnoid granulations which protrude into the major venous sinuses, especially the superior sagittal sinus at the vertex of the skull. The CSF canals are lined by ependymal cells, from which ependymomas arise. These tumours are therefore related in space to the ventricular system.

Figure 30.5 The ventricular system, showing the CSF pathways. See text for further details.

Disturbance in the flow or absorption of CSF causes hydrocephalus. Obstruction of the flow before the exit foramina in the fourth ventricle leads to ‘obstructive’ hydrocephalus. Obstruction of the arachnoid granulations leads to ‘communicating’ hydrocephalus.

In neuro-oncology, tumours most commonly cause obstructive hydrocephalus. This is normally the result of obstruction in the fourth ventricle, by tumours growing in or around the ventricle (such as medulloblastoma or ependymoma), or within the cerebellum (most commonly metastases). The next most common location for obstruction is the aqueduct, from compression by tumour in adjacent brain or the pineal gland. More proximal obstruction can also occur at the foramen of Munro, usually from infiltrative high-grade glioma, causing hydrocephalus in one or both lateral ventricles.

Communicating hydrocephalus can be caused directly by tumour, when extensive meningeal involvement occurs. This is almost always metastatic (most commonly from breast cancer), and it is rare. A commoner cause of communicating hydrocephalus in neuro-oncology practice, is blood in the CSF, resulting from surgery or a spontaneous bleed directly from a tumour. Blood can occlude the pores in the arachnoid granulations. Often this resolves spontaneously but, occasionally, a CSF shunt (such as a ventriculoperitoneal (VP) shunt) must be inserted. Infection is also a cause, through the same mechanism.

Anatomy of the skull and meninges

The skull itself is divided into three fossae. The frontal fossa contains the frontal lobe; the middle cranial fossa contains the temporal lobe; the posterior cranial fossa contains the cerebellum. The cerebellum is divided from the rest of the cranial contents by the tentorium cerebelli (‘tent’), except for an aperture through which the brainstem passes. The two cerebral hemispheres are divided by the falx cerebri. These two structures are composed of layers of tough meninges, and are designed to ‘damp’ movements of the brain which might otherwise be damaging to the delicate brain substance. They are relatively rigid. The falx and tentorium cannot be infiltrated by gliomas, and so present efficient barriers to their spread. Meningiomas, on the other hand, can spread along their surface, and their potential direction of spread can be appreciated by understanding this anatomy.

The meninges consist of three layers. The outer dura mater (usually known simply as dura) is a tough membrane, which acts like a periosteum; it is the part visible on imaging, and forms the falx and tent. Below and closely applied to the dura is the arachnoid mater. Below this lies the pia mater, a thin delicate layer which covers every surface and fold of the brain substance. In some places, there is a space (the subarachnoid space) between the arachnoid and pia, crossed by thin strands with a cobweb-like appearance (hence the origin of the name arachnoid). The dura lines the whole cranial cavity, including the skull base. In some areas, the dura splits to form venous channels, such as the superior sagittal sinus, and the cavernous sinuses. It also forms two important folds, the tentorium cerebelli and the falx cerebri, which are continuous with the dura covering the skull vault and skull base.

Clinical features – presentation of brain tumours

Presenting symptoms and signs of CNS tumours are characteristic; patients may present with one or more classes of symptoms, as follows.

Specific focal neurological deficit

CNS tumours may make their presence known by local damage, leading to specific deficits dependent on the location of the tumour. For example, a meningioma affecting the motor cortex will produce weakness and stiffness typically in a limb, specifically depending on which part of the motor cortex is affected. A glioblastoma affecting the frontal lobe produces intellectual, motivational and memory problems. In this way, symptoms and signs indicate the site of the tumour, which can be confirmed with imaging. Tumours arising in eloquent areas typically present earlier than those in silent areas of the brain, simply because they produce symptoms when they are smaller. Tumours which grow slowly, for example meningioma, produce an insidious onset, with relatively mild symptoms and signs, despite often being surprisingly large when detected. Tumours which grow rapidly, and destructively, such as glioblastoma, produce symptoms and signs which often appear to commence abruptly.

Symptoms and signs relating to specific parts of the brain are as follows:

• frontal lobe – intellectual impairment and personality change.

• parietal lobe – sensory or visual inattention.

• fronto-temporo-parietal – speech disturbance, especially dysphasia

• occipital lobe – visual field defects.

• brainstem – cranial nerve defects, sensory or motor disturbance.

• cerebellum – loss of coordination of movement.

Epileptic seizure

Almost all CNS tumours can potentially cause epileptic seizures (as can craniotomy to treat them). These can take a number of forms, including generalized ‘grand mal’ seizures, ‘Jacksonian’ motor seizures, sensory seizures, and ‘petit mal’ absence attacks. Seizures are typically associated with slow-growing, low-grade gliomas, especially oligodendrogliomas. Seizures will often bring a tumour to light before other symptoms and signs and, for that reason, the presence of seizure is associated with a slightly improved survival in patients with high-grade glioma. Most patients are controlled with simple anticonvulsant medication, but where this is problematic, the advice of a neurologist is valuable.

Raised intracranial pressure

Raised intracranial pressure (ICP) typically produces a triad of symptoms: headaches, which are typically worse in the morning; nausea and vomiting; and papilloedema (oedema of the optic disk). Raised intracranial pressure most commonly arises as the result of obstructive hydrocephalus, and is therefore particularly associated with tumours in the posterior fossa. This can also be associated with drowsiness, mild confusion and sometimes with personality change.

Non-specific symptoms

Non-specific symptoms are common, and typical of CNS tumours. Such symptoms may be very difficult to identify as significant in the early phase of the illness. Headache, which may be local or generalized, but not related to raised ICP, occurs in some patients. The other characteristic symptom, particularly of high-grade glioma, is tiredness. Early symptoms may be frustratingly non-specific, and a patient who complains of vague headache, tiredness and feeling off color is not likely to be investigated for a primary CNS tumour.

Principles of management

Although most patients come to oncology with a definitive diagnosis, it is important for oncologists to contribute to the multidisciplinary management of CNS patients.

Diagnosis – a combination of history, imaging and pathology

In neuro-oncology, perhaps more than any other area, it is helpful to combine information from the patient’s history and examination findings, as well as imaging results and histology in determining the definitive diagnosis. The history and physical signs, especially the duration and any family history, may indicate a likely diagnosis or help to indicate whether the condition is a high-grade malignancy rather than a low-grade or benign tumour.

Typically, the diagnosis is suggested by computed tomography (CT) or magnetic resonance imaging (MRI). In some tumour types, such as vestibular schwannoma (acoustic neuroma), imaging is definitive; in other cases, imaging offers only a differential diagnosis. Classical difficulties arise in distinguishing glioma from primary cerebral lymphoma, and solitary metastasis from abscess or small glioma. Benign lesions can also have imaging appearances suggestive of malignancy. Therefore, biopsy is crucial for obtaining a definitive diagnosis.

Some CNS tumours, especially gliomas, are rather heterogeneous, and it is understood that biopsy material may not necessarily be representative of the whole tumour. Occasionally, it may contain necrotic material only. Thus, clinical history and imaging appearances must also be considered in defining the exact diagnosis.

Performance status in the treatment decision

Performance status is an important predictor of outcome, including survival, particularly for patients with glioma (Table 30.2). It also indicates how well the patient is likely to tolerate treatment. This is an important factor when recommending a treatment program. The choice can be between radical, palliative, or active supportive care. For patients with disabling neurology, especially those with GBM, supportive care may be the most appropriate option.

Table 30.2 WHO performance status and Glasgow coma scale (GCS).

The WHO Performance Status is useful in assessing patient capabilities, especially with respect to activities of daily living. The Glasgow Coma Scale (GCS) is a measure of conscious level.

WHO performance status
0 = Able to carry out all normal activity without restriction
1 = Restricted in physically strenuous activity but ambulatory and able to carry out light work
2 = Ambulatory and capable of all self-care but unable to carry out any work; up and about >50% of waking hours
3 = Capable of only limited self-care; confined to bed or chair >50% of waking hours
4 = Completely disabled. Cannot carry out any self-care; totally confined to bed or chair
Glasgow Coma Scale (GCS)
Eyes open	Spontaneously	4
	To speech	3
	To stimulus	2
	None	1
Best verbal response	Orientated	5
	Confused	4
	Inappropriate words	3
	Incomprehensible	2
	None	1
Best motor response	Obeys commands	6
	Localize stimulus	5
	Flexion – withdrawal	4
	Flexion – abnormal	3
	Extension	2
	No response	1
Best score 15
Worst 3

Principles of neurosurgery

The acquisition of histological material to define the diagnosis is extremely important. However, in many cases, there is also a role for a more extended procedure to debulk or remove the tumour, and relieve pressure effects (see sections on individual tumours). Surgical decompression improves symptoms quickly, allows reduced steroid doses, and facilitates radiotherapy, especially in patients with high-grade gliomas (HGGs).

Occasional HGGs grow with a cystic component to the tumour. If fluid reaccumulates, then a small catheter can be placed into the cyst and attached to a subcutaneous (Ommaya) reservoir. By inserting a needle through the skin, fluid can be aspirated without the need for a further surgical procedure.

Patients who present with, or develop, hydrocephalus may need a shunting procedure to redirect the flow of CSF. In adults, this is usually done with a ventriculoperitoneal (VP) shunt. Some patients with obstructive hydrocephalus can be successfully treated by a third ventriculostomy, avoiding the need for a shunt. In this procedure, a perforation is made in the floor of the third ventricle, allowing CSF to escape, and circumventing the obstruction.

Principles of radiotherapy planning for CNS tumours

The fundamental principles of radiotherapy (RT) planning and treatment delivery apply to CNS tumours. These include accurate and reproducible immobilization, high quality imaging to localize the tumour and critical normal structures, three-dimensional conformal or intensity modulated planning, and high precision treatment delivery.

Immobilization devices include Perspex or thermoplastic beam direction shells or, where a higher precision is required, a relocatable stereotactic head frame. The optimal position for the patient depends on the location of the tumour, and on the immobilization devices available. A supine position is more comfortable for the patient. Using couch extensions, such as an ‘S’ frame or a relocatable stereotactic radiotherapy (SRT) head frame, allows treatment of posterior lesions with the patient supine. With a Perspex or thermoplastic shell, patients with posterior lesions need to be treated prone, to allow appropriate beam directions without collision with the couch. The exception is for palliative RT, using parallel-opposed lateral fields, where the patient can be positioned supine. For craniospinal axis treatment, a prone treatment position allows palpation of the spine and accurate visualization of matching field junctions. There is no role for lateral shells, which are unstable and uncomfortable. Shells should be cut out to improve skin sparing.

Most planning is based on CT, because this delivers exact patient geometry and position without distortion, and because CT density is required for accurate dosimetry calculation. Preferably, intravenous contrast should be used because this enhances discrimination of the target. Although this changes the CT numbers slightly, dosimetry is affected by 1% or less. In most circumstances, tumours are less well demonstrated on CT than on MRI, and MRI should be considered an essential modality for planning. Typically, MRI does not have to be performed in the treatment position, provided suitable image coregistration software is available. The correct choice of MRI sequence must be made, in order to optimize definition of the tumour. However, CT and MRI are complementary. While MRI is in general the better modality for showing tumour, CT is extremely useful to determine the extent of bone involvement, or the extent of a non-invasive tumour which is limited by bone. In the next few years, additional imaging is likely to be incorporated into planning, especially for gliomas. This includes newer MR sequences (such as diffusion weighted and diffusion tensor imaging), MR spectroscopy and PET (positron emission tomography) imaging. In some meningiomas that have been completely resected, coregistration with the preoperative MRI may be helpful in determining the location of the tumour and possible spread.

The definitions of gross tumour volume (GTV), clinical target volume (CTV) and planning target volume (PTV) as outlined in ICRU 83 should be used for planning purposes. Imaging shows the extent of the GTV; historical data are used to define a CTV margin around it, which is typically the same in all patients with the same condition. The PTV margin is designed to account for uncertainties in planning and treatment, and has systematic (i.e. ‘treatment preparation’) and random (i.e. ‘treatment delivery’) elements. The margin should be added based on the recipe formula outlined the British Institute of Radiology 2003 report ‘Geometric Uncertainties in Radiotherapy’, and incorporated into ICRU 83.

Conformal radiotherapy should be considered standard practice, because this limits dose to normal tissues. There is reasonable evidence that this in turn reduces complications in patients treated for CNS tumours, by reducing the volume of tissue, especially brain, receiving a high dose, or avoiding exposure to sensitive structures, such as the hypothalamus and pituitary gland (conformal avoidance). Eye lens doses should be estimated with thermoluminescent dosimetry (TLD) for future reference. On-treatment portal films or images should be used to confirm positioning for radical treatments.

Normal tissue tolerance to radiotherapy

Normal tissue tolerance is an important concept. It embodies both the risk of a complication and also the severity of its effect on the patient. The relevance also depends on the clinical setting: a higher risk of normal tissue damage might be accepted in a patient with a highly malignant tumour requiring a high RT dose who has only a low chance of long-term survival, than is reasonable in a patients with a benign tumour. The dose that is considered safe may therefore vary from one condition to another.

There is almost certainly a volume effect in normal tissue tolerance of CNS structures, as in other parts of the body. This means that the larger the volume irradiated, the lower the safe dose. The CNS is also particularly sensitive to the dose per fraction, and many of the dose-fractionation schedules used are designed to take advantage of this. Many of the data on tolerance in the CNS are based on literature reports which predate the use of modern imaging, especially MRI. Tolerance doses are thus far from absolute.

Tolerance of the brain itself (to avoid necrosis) is in the region of 54–60 Gy in approximately 30 fractions, depending on volume treated and dose per fraction. A volume effect also exists for intellectual damage. Using 3D conformal RT, intellectual damage in adults is uncommon with doses up to 54 Gy in 30 fractions. The brainstem is said to have a slightly lower tolerance than brain substance, approximately 54 Gy in 30 fractions (or 55 Gy in 33 fractions). The optic nerves and chiasm are also thought to be more sensitive than brain parenchyma. For benign tumours in this region, a dose of 45 Gy in 25 fractions to 50 Gy in 30 fractions should be safe, with a risk of blindness which is virtually zero.

The pituitary gland and hypothalamus have a much lower tolerance for hormonal dysfunction. There is probably little effect for doses under 20–24 Gy, but adults in whom these structures receive 40–60 Gy have a significant long-term risk of hypothalamic–pituitary axis dysfunction.

The lacrimal gland shows reduced tear output after doses over about 20 Gy (similar to salivary glands). The lens of the eye should not develop cataract after doses less than 5–6 Gy, spread out over 30 fractions. There is a 50% risk of cataract after a dose of 15 Gy. The middle and inner ears are also sensitive structures but in adults recover in most patients after doses up to 60 Gy. The risk of permanent alopecia depends on the dose to the hair follicles in the dermis. The risk is very low with doses below 10–15 Gy, but 50% of patients will develop permanent alopecia after 43 Gy (in 30 fractions) to the scalp. This dose is difficult to estimate routinely because the hair follicles normally fall within the build-up region.

The spinal cord has a tolerance of approximately 50 Gy in 30 fractions (equivalent to 46 Gy at 2 Gy per fraction). This may be a conservative (i.e. safe) estimate and, in some circumstances, higher doses may be appropriate, such as for GBM of the spinal cord.

Principles of steroid therapy

Steroids are used to treat oedema in the brain, caused by tumour or surgery, so many patients attend the neuro-oncology clinic already taking a steroid such as dexamethasone. A daily dose of dexamethasone (Dex) of 16 mg is considered the highest useful dose in most circumstances. This is a typical dose used perioperatively, and is usually reduced as quickly as possible. Patients on anticonvulsant drugs, which increase the metabolism of dexamethasone, occasionally benefit from higher doses in the palliative setting.

In patients requiring RT where significant intracranial pressure remains, steroid is needed, and may need to be increased during the course. However, there is no absolute indication for steroids during radiotherapy. In patients in whom surgery has relieved intracranial pressure, none may be necessary. It is thus possible to reduce steroid doses during a course of RT.

Dexamethasone has important side effects, which can impact seriously on quality of life. These include increased appetite, weight gain, muscle weakness, gastric irritation, and diabetes. Rarely, it causes psychosis which is very distressing and difficult to manage. Patients should be managed with the minimum possible dose. For reduction, the dose must be tailed off slowly, and not stopped abruptly. Patients should also be issued with a steroid card.

Principles of additional supportive care

It is important to think holistically about patients with CNS tumours. This includes biological, psychological, social and cultural aspects of their care. This patient group is very diverse, with a wide range of diagnoses and prognosis, and the problems experienced by the patients therefore vary greatly. Even patients with benign tumours may experience major problems, even if these are not life threatening. For example, the seriousness of the condition is obvious in a patient with weakness due to GBM undertaking palliative treatment. However, hearing loss due to vestibular schwannoma can also have a distressing impact on a young patient who needs to hear for childcare or work.

Supportive input may be valuable to a patient throughout their journey. Needs vary according to tumour type, and may fluctuate throughout the patient’s journey, with treatment or progression. Many patients benefit from practical and psychological support. The relevant support is often best developed by a specialist nurse, who will be part of most neuro-oncology teams. Key roles are liaison with the patient and family, other healthcare professionals and hospice services, and provision of information from local or general resources, such as Cancer BACUP (http://www.cancerbacup.org.uk/Home). For some patients, especially those with gliomas, financial benefits may be available.

Driving after a diagnosis of CNS tumour

Many patients with primary CNS tumours are not allowed to drive following the diagnosis. This is because there is a risk of seizure as the result of the tumour. There is also a small risk of seizure following craniotomy, whatever the underlying condition. In particular, patients with high-grade gliomas have their driving licenses revoked for 2 years, timed from the completion of treatment.

Decisions about licensing are made by the Driver and Vehicle Licensing Authority (DVLA), though with information provided from the clinical teams. In general, the DVLA will help patients to regain a license, and will provide an individualized decision in unusual circumstances. The DVLA provides information on the guidelines for return of licenses for medical practitioners which can be obtained from the DVLA website (www.DVLA.gov.uk). It is worth using this on-line facility, since the regulations do change from time to time.

Individual tumour types

High-grade gliomas

Pathology and clinical features

Glioblastoma (GBM) is the commonest primary CNS tumour in adults (see Figure 30.2). GBMs and grade III gliomas are collectively known as high-grade gliomas (HGGs). The major problems with high-grade gliomas are: