Radiotherapy & Chemotherapy for CNS Tumours Flashcards
What type of brain tumour has the highest lethality?
high-grade gliomas
they are one of the commonest causes of cancer deaths in the young
What are the predisposing factors to gliomas?
there are few known aetiological factors
prior radiation exposure can lead to a brain tumour a decade or so later
How do high grade gliomas usually present?
high grade glimoas present almost exclusively as emergency cases with short history and new neurological signs
How do brain tumours affect patients’ lives?
- loss of job, driving license and independence
- strain on relationships - anxiety, personality change, memory loss, need for care
- financial worries
- seizures and the uncertaintly about when they will occur
What are the 4 main categories of brain tumours with examples?
high grade glioma:
- especially glioblastoma
low grade glioma:
- often exists for many years and changes very little
- has very subtle impacts on the patient and their cognitive ability
- can transform into high grade glioma
benign tumours:
- meningiomas
- pituitary adenomas
- schwannomas
paediatric:
- medulloblastoma
- germ cell
- ependyoma
What are the main implications of benign tumours?
there is a fixed volume within the skull
growth of benign tumours can start to compress and interfere with the function of the normal brain
they are usually treated surgically
What is a glioma?
a type of tumour that starts in the glial cells of the brain or spinal cord
How do brain tumours usually present?
pressure symptoms:
- headache (50%)
- nausea and vomiting
- confusion
- reduced conscious level
seizures:
- in 50% of cases
focal symptoms due to location:
- e.g. weakness, dysphasia
- presentation varies a lot between patients as focal symptoms depend on the area of the brain affected by the tumour
When should someone be referred for a head scan by a GP?
if they present with BOTH a headache and another neurological sign/symptom
What are the different treatments available for brain tumours?
- steroids
- anti-epileptics
- surgery
- radiotherapy
- chemotherapy
Why are steroids used to treat brain tumours?
What are the drawbacks of using steroids?
they are used to reduce the swelling in the brain
it improves condition in the short-term, but long-term use can lead to adverse effects
can cause diabetes, high blood pressure, muscle weakness, etc.
the patient should be given the lowest dose of steroids that is appropriate
What is usually the first symptom of brain tumour?
headache
By the time they have presented to hospital, what symptoms does a brain tumour patient often present with?
- headache
- seizures
- unilateral weakness
- dysphasia
- confusion
- personality change
How can raised intracranial pressure affect the brain?
it leads to global neurological deficits
Why is it important to know where the central and lateral sulci are present?
they divide the brain into 4 lobes
presentation relates to whereabouts in the brain the tumour is present
Which area is usually concerned with language?
the dominant hemisphere - which is usually the left
What would indicate a brain lesion rather than a spinal cord lesion?
if symptoms e.g. weakness affected the whole of one side, rather than just part of it
If a patient had a brain lesion either side of the central sulcus of in the left hemisphere, what would you expect?
this affects both motor and sensory functions as it is in the left fronto-parietal region
unilateral (right side) numbness and weakness
What may make you suspect a brain tumour rather than a stroke?
if there is a gradually progressive history
a stroke or vascular disorder would present more suddenly
What would happen if someone had a brain lesion in the left temporo-frontal region?
they would present with expressive aphasia
the patient can understand everything that is being said to them, but no one else can understand what they are trying to say
What types of symptoms would someone present with if they had a brain lesion in the frontal region?
they tend to develop subtle symptoms involving an altered personality
frontal regions are involved in higher order functioning such as social skills, time keeping and planning
the patient becomes very passive, withdrawn and apathetic
What type of brain lesion involves sensory problems?
lesions in the parietal lobe
this leads to loss of sensation and dyspraxia
this is a condition affecting physical coordination
What is radiotherapy?
the use of X-rays to treat tumours
carefully controlled high energy X-ray beams are focused on the tumour
the beams travel through the skin to the tumour so are painless and invisible
What are the benefits to using radiotherapy?
- non-invasive
- no anaesthetic is required
- can be given to patients with multiple comorbidities in which surgery would not be possible
- can treat hidden areas that would not be accessible to surgery
When is radiotherapy indicated to improve survival in high-grade (grade 3 and 4) gliomas?
it is proven to increase survival by 6-12 months dependent on grade of tumour, age and performance status (PS) of each patient
may improve PS in 1/3 of patients
What is the main benefit of using protons over photons (radiotherapy)?
protons will go to a certain depth inside the paitent and then they largely stop
the dose of protons can be aimed and delivered in a concentrated way
there is minimal effects on other structures outside of the target site
When are protons always preferred to be used over photons?
in children with malignancies to minimise the dose to the rest of the body and minimise risk of growth problems
when a tumour has a critical structure just beyond it, a limited dose will reach the critical structure
When is radiotherapy NOT recommended?
elderly or patients with poor PS that may die from the brain tumour within 3-12 months before they have recovered from the side effects of RT
When is radiotherapy recommended for high grade gliomas?
in patients who are young and fit with a grade 3 tumour
they could live for several years after RT
What are the acute side effects of cranial radiotherapy?
these occur during or a few weeks after RT
- cerebral oedema causing raised ICP & exacerbation of pre-RT neurological symptoms
- hair loss at the site of RT
- scalp / ear erythema
What are the intermediate side effects of cranial radiotherapy?
these occur within a few weeks / few months
somnolence syndrome:
- severe tiredness & exacerbation of existing neurological symptoms
What are the late side effects of cranial radiotherapy?
these occur several months / years after RT
they are caused by damage to sensitive structures
- damage to lens - cataracts
- damage to pituitary gland - hypopituirarism
- damage to cerebral hemispheres - memory loss
most long term effects are subtle and do not impact the lvies of patients very much
What is the median survival for grade 1-4 gliomas following treatment?
grade 1 - many years or a cure
grade 2 - 5 to 12 years
grade 3 - 2 years
grade 4 - 9 months
For which types of brain tumours can treatment be curative?
certain rare CNS tumours such as germ cell tumours and medulloblastoma
by using RT, surgery, chemotherapy or a combination
What type of radiotherapy is used for brain metastases?
whole brain RT
this is used to treat metastases in the brain which may not be seen
the patient is noticably affected e.g. complete hair loss, extreme tiredness
this is palliative
When should chemotherapy be used to treat brain metastases?
if the primary tumour is chemosensitive
e.g. small cell lung cancer
When should gamma knife be considered for treatment of brain metastases?
if low volume disease, good performance status and reasonable prognosis
this can pick off specific bits of disease within the brain
What do patients go through in the planning and administration of radiotherapy?
- having their mask made to hold their head in place
- scan in the mask for planning the RT
- up to 6 weeks of RT with 5 treatments per week
When is chemotherapy used in treating brain tumours?
- can be used pallatively to improve symptoms
- can be used to enhance the effectiveness of radiotherapy and improve outcome
What types of findings tend to be present in a brain tumour?
- raised intracranial pressure
- epilepsy
- neurological deficit
- endocrine dysfunction
- incidental finding
What symptoms result from raised intracranial pressure?
- headaches (early morning)
- vomiting
- blurred vision
What tends to cause raised intracranial pressure?
tumour mass
surrounding oedema
obstructive hydrocephalus:
- when the flow of CSF is blocked along one or more of the narrow passages connecting the ventricles
What are the 2 different types of seizures?
In what type of tumour are they often seen?
focal and generalised seizures
they are seen as a symptom in supratentorial tumours
What is a supratentorial tumour?
a tumour that is present above the tentorium cerebelli
What is the difference between focal and generalised seizures?
focal seizures:
- disruption of electrical impulses in one part of the brain
generalised seizures:
- impairs consciousness and distorts the electrical activity of the whole or a larger portion of the brain
What are the different types of neurological deficit that can result from brain tumours?
- cognitive
- visual
- cranial nerve
- motor
- sensory
What is shown here?
a type of neurological deficit resulting in visual problems
How may a brain tumour be an incidental finding?
cranial imaging for other reasons
usually meningiomas / pituitary tumours
What is looked for in an examination for a brain tumour?
- higher mental function
- cranial nerve abnormality
- motor / sensory problems
- cerebellar signs
what investigations are performed in a suspected brain tumour?
- haematological
- tumour markers - aFP, Bhcg, PSA
- hormonal assay
- visual fields
- chest / abdominal CT
What different types of imaging are used to look for a brain tumour?
- CT scan
- MRI
- cerebral angiography
What is involved in the management of brain tumours?
- surveillance
- medical
- steroids - dexamethasone
- anti-convulsants
- hormonal replacement
- surgical
- adjuvant therapy
What is meant by adjuvant therapy?
treatment that is given in addition to the primary (initial) treatment that will help reach the end goal
adjuvant therapy for cancer usually refers to surgery followed by chemo- or radiotherapy to decrease the risk of the cancer recurring
What is the role of surgery in treating brain tumours?
- it can be diagnostic
- it can remove the mass effect and alleviate symptoms
- treat complications
What are the surgical options for brain tumour?
biopsy:
- stereotactic
- neuro-navigation
- endoscopic
- free hand
excision:
- total
- partial
what is a stereotactic biopsy?
a procedure that uses a computer and imaging performed in at least two planes to localise a target lesion and guide the removal of tissue for examination
What is neuronavigation?
computer-assisted technologies used by neurosurgeons to guide or “navigate” within the confines of the skull or vertebral column during surgery
What is a frozen section used to look at?
it is used to confirm the presence of abnormal tissue
it can be difficult to establish whether some intrinsic tumours are normal/abnormal operatively
oedema surrounding the tumour can look abnormal
What is shown here?
IIIrd ventricular tumour
What is a IV ventricular ependymoma?
ependymomas of the fourth ventricle are rare brain tumours that arise from the cells that line CSF containing structures
e.g. central canal of spinal cord, surface of cerebral ventricles
What is shown in this image?
endonasal resection craniopharyngioma
When are gliadel wafers used?
gliadel is a wafer that contains the chemotherapy drug carmustine
the neurosurgeon puts the wafer into the brain during surgery to remove the tumour
After surgery to remove a brain tumour, what may be performed?
- further surgery
- radiological surveillance
- adjuvant therapy - chemo/radiotherapy
What can be performed if hydrocephalus occurs as a complication of surgery?
accumulation of CSF occurs within the brain, leading to increased pressure inside the skull
- third ventriculostomy
- ventriculo-peritoneal shunt
