Brain cancer

Question 1

What is cancer?

Answer 1

Disease that results when cells undergo cellular change causing proliferation and uncontrolled growth of abnormal cells.
Cells within the body, naturally go through a cellular life expectancy and death and undergo a natural process of apoptosis
Cancer cells grow uncontrollably and at different rates and do not die a natural, normal death within their life cycle.
Most tumour cells reach the brain by haematogenous spread, usually through arterial spread.

Question 2

Risk factors for brain cancer

Answer 2

Age
Gender
Environmental exposures Family History
Race & Ethnicity
Ionizing Radiation
Head trauma

Question 3

Clinical signs and symptoms for brain cancer

Answer 3

Clinically present with:
• headaches,
• seizures,
• mental status alterations,
• ataxia, nausea & vomiting,
• change in behaviour & personality and
• altered visual habits.

Question 4

Types of brain tumours

Answer 4

Cerebral Abscess, GBM, Stroke, Meningioma, Cerebral Venous Thrombosis

Question 5

Pathophysiology

Answer 5

Within the brain, metastasis or secondary brain tumours are most commonly found in the area beneath the grey/white junction.
There are these areas classed as ‘watershed’, which are the zones on the border of major blood vessels (such as blood vessels of the COW)

Question 6

Tests for brain mets

Answer 6

• Complete Blood Count
• Chest radiograph
• CT Brain +/- iodinated contrast
• MRI Brain
• PET Scan
• Biopsy (not usually needed if a primary cancer of another origin is known)

Question 7

CT for brain mets

Answer 7

• Often first line of imaging for acute neurological deficits.
• Pre contrast scan will show signs of vasogenic oedema. The lesion could be isodense, hypodense or hyperdense.
• Post contrast scan will show a hypodense lesion
• Easily accessible

Question 8

MRI for brain mets

Answer 8

 Gold standard of imaging in
Brain Metastases. Replaced CT in the 1980’s.
 T1, T2, FLAIR and DWI

Question 9

NM for brain mets

Answer 9

 FDG PET:

• One of the best tools for imaging metastases however can only detect mets up to 1.5cm in size.
• Lung, breast, colorectal, head and neck, melanoma and thyroid mets present usually as hypermetabolic
• Any central hypometabolism is suggestive of necrosis.

Question 10

Treatment for brain mets

Answer 10

Corticosteroids - Corticosteroids are usually indicated in any patient with a malignant brain tumour and symptomatic peritumoral oedema. Most commonly used – Dexamethasone.

Radiotherapy – treatment of choice, WBRT.

Surgical Therapy - Surgical therapy plus post-operative WBRT is now an established treatment for patients with surgically accessible single brain metastases

Radiosurgery - Stereotactic radiosurgery is a method of delivering intense focal irradiation using a linear accelerator. Generally used on patients with lesions less than 3cm diameter.

Chemotherapy - not usually the primary therapy for most patients and is seldom the only therapy. Potentially for use for patients with small, asymptomatic tumours from primaries that are known to be chemo sensitive

Question 11

What is a Glioma

Answer 11

Glioma is an umbrella term used to describe a group of brain tumours that arise in the glial brain cells.

Between 2007-2011 the incidence of Gliomas was 6.6 per 100,000 people with close to half of these gliomas being Glioblastomas.

Glioma encompasses:
• Astrocytomas (slow growing - usually benign)
• Oligodendrogliomas
• Oligoastrocytomas
• Glioblastoma (rapidly growing - malignant)

Question 12

Glioblastoma

Answer 12

Most common adult primary intracranial neoplasm. Generally very aggressive and have often poor prognosis (no longer than two years normally)

Noteworthy feature of a GBM is that they can cross hemispheres using corticospinal tracts in the corpus callosum

Clinically present with focal neurological deficit, symptoms of increased intracranial pressure & seizures

Spreads quickly and invades the brain with tentacle-like projections making it harder for resection.

GBM v Glioma: A GBM is a malignant glioma, arising in the glial brain cells.

Differentials:
Metastasis, Lymphoma, Abcess, Astrocytoma, Infarction

Question 13

CT for Glioblastomas

Answer 13

• Often first line of imaging.
• Marked mass effect
• Surrounding vasogenic oedema
• Calcification is uncommon
• Easily accessible

Question 14

MRI for Glioblastomas

Answer 14

 T1, T2, FLAIR, DWI & MR
Perfusion.
 Double rim sign not visible to distinguish from an abscess.
 Follow up source of imaging.
 Postoperatively used in the first 24-48hrs or assess residual disease.

Question 15

NM for Glioblastomas

Answer 15

 FDG PET:

• Allows for differentiation between high and low grade tumours
• High grade demonstrate high glucose uptake
• Struggles to allow differentiation between glial and metastatic disease

Question 16

Treatment for Glioblastomas

Answer 16

SURGERY
• With newly diagnosed GBM the standard of care is a maximal safe surgical resection.
• Imaging plays a major role in the pre surgery approach, recognising the size and location of the neoplasm.

RADIOTHERAPY
• Used in conjunction with a surgical approach this is the mainstay of treatment of patients with GBM’s for decades.
• Local recurrence within 2cm of the initial tumour margin is the main failure following treatment.
• Can cause cognitive impairment

CHEMOTHERAPY
• Can be used on low grade gliomas

Question 17

What are Meningiomas

Answer 17

o Most common type of benign brain tumour that arises in the Central Nervous System.
o As many as 90% are benign. Slow growing, extra axial tumours.
o Forms in the meninges that cover the brain, and also the spinal cord. Does
not arise in the glial cells.
o Growth of these space occupying lesions can become fatal. o Low rate of recurrence post surgery.
o 2:1 ration women:men

Question 18

Clinical presentation for meningiomas

Answer 18

Often meningiomas are incidental findings and are asymptomatic.
Large space occupying meningiomas with surrounding oedema can have patients clinically present with the following:
• Headache
• Change in mental status
• Paresis (muscle weakness, part paralysis)

Question 19

CT for meningiomas

Answer 19

• Contrast enhancing CT necessary
• Homogenously enhance with contrast
• Slightly hyperdense next to adjacent normal brain
• Calcification is not uncommon
• Easily accessible

Question 20

MRI for meningiomas

Answer 20

 Contrast enhancing MRI
necessary
 Gold standard for diagnosis and characterisation
 T1, T2, FLAIR, DWI & MR Perfusion.
 Homogenous
 Well circumscribed

Question 21

Angiography for meningiomas

Answer 21

 DSA

• Allows for preoperative embolization – to reduce intraoperative blood loss during resection.
• Mother-in-Law sign “comes early, stays late and is very dense”.
• Often have a dual blood supply

Question 22

Treatment for meningiomas

Answer 22

Decision to treat a meningioma is dependent on tumour size and associated symptoms. Many may simply be observed over time.
Surgical Resection
Radiation Therapy
Hormonal Therapy Chemotherapy