Central Nervous System Tumors Flashcards
What are the two types of CNS tumors?
Primary: These tumors start in the brain or spinal cord and can be benign or malignant. They can spread to other parts of the brain or spinal cord, but rarely to other parts of the body.
Secondary/ (metastatic):These tumors start in another part of the body, such as the lungs or breast, and spread to the brain or spinal cord. They are more common than primary tumors and are always malignant. Up to half of metastatic brain tumors come from lung cancer.
20 to 40% of patients develop brain metastases.
What percentage of CNS tumors involve the brain?
About 80% involve the brain, and 20% involve the spinal cord.
What is the most common malignant specific tumor in adults?
Glioblastoma multiforme (GBM) is the most common malignant specific type of tumor in adults
Glioblastoma multiforme is one of the most aggressive forms of brain cancer, with only 6.9% of patients surviving 5 years (evolving statistics)
What is the most common malignant CNS tumor in children?
At what age does it often occur?
Medulloblastoma
Originates in the fourth cerebral ventricle and the cerebellum, and often invades the meninges
often occurs before age 10
medulloblastomas are the 2nd most common childhood brain tumor
What is the most common classification of brain tumors
Gliomas
In regards to the tentorium
adult tumors are more common above or below it?
children’s tumors are more common above or below it?
Adult brain tumors are more common above the tentorium, and children’s brain tumors are more common below it
What is the tentorium?
The tentorium cerebelli is an extension of the dura mater and divides the cerebrum and cerebellum
What is the most common CNS tumor in children?
not the most malignant one the other one
Astrocytoma, a slow-growing type of glioma, is the most common tumor in children
They commonly develop in children ages 5 through 8
Where do Astrocytomas originate?
Originates in the brainstem, cerebellum, white matter of the cerebrum, or spinal cord
What is the most common benign Brain tumor overall?
Meningioma
Brain tumors account for what percent of all malignancies?
1.4%
Brain tumors occur primarily in children of what age?
3-12 years old
Brain tumors occur in adults primarily of what age?
50-80 years old
What is the leading cause of cancer death in children?
Brain cancer
What is the blood-brain barrier (BBB)?
A protective barrier that prevents toxic substances from entering the brain and CSF.
Lipid-soluble substances can pass through, but water-soluble ones require a carrier molecule. Examples: glucose, some amino acids, and sodium
Which chemotherapy drug class can cross the blood-brain barrier?
Nitrosoureas
What are the three most important prognostic indicators for CNS tumors?
Age, performance status, and tumor type
Tumor grade is more important than size
Also important is the presence or absence of necrosis
Gliomas tend to spread invasively because they don’t form a natural capsule that inhibits growth
What is the function of the Karnofsky Performance Scale (KPS)?
It measures the patient’s ability to perform daily tasks and helps determine prognosis.
mentioned in the hidden notes of the powerpoint
What is the dose tolerance for whole brain radiation?
dose tolerance
4500 cGy
What is the typical dose tolerance for treating CNS tumors with partial brain radiation?
1/3 of brain
6000 cGy.
Dose Tolerance for Brainstem (Whole)
5000 cGy
Dose Tolerance for Optic Nerve
5000 cGy
Dose tolerance for Retina
4500 cGy
Dose tolerance for Ear
3000/5500 cGy (acute/chronic)
Dose tolerance for Spinal cord (20 cm^2)
4700 cGy
Spinal Cord compression is always an___________
Emergency
Radiation therapy will likely be administered as immediately as possible to prevent further damage
What are common side effects of radiation therapy to the CNS?
Hair loss, erythema, fatigue, radiation necrosis, and cognitive effects (especially in children).
What is CSF composed of?
CSF is composed of proteins, glucose, urea, and salts
What is the purpose of CSF?
Its roles include buoyancy to protect brain, helping to control the chemical environment of the CNS, and a means of nutrient/waste exchange
What does blockage of the CSF causes______
building up of CSF in the cranium and causing hydrocephalus
Brainstem Gliomas have what kind of prognosis?
A poor one
(and we know this because gliomas spread aggresively because they are not encapsulated & in the brainstem of all places…)
Are Schwannomas usually benign or malignant?
Schwannomas are usually benign for reasons not yet understood
less than 1% become malignant
Schwannomas are a benign nerve sheath tumor
The Schwannomas that do become malignant (about 1%) are called…
neurofibrosarcoma
Schwannomas Heterogenous or Homogenous tumors?
Schwannomas are homogeneous tumors, consisting only of Schwann cells.
What are typical presenting symptoms of CNS tumors?
Benign tumors generally cause symptoms related to pressure
Increased intracranial pressure can result from blocked CSF flow (hydrocephalus)
Malignant lesions cause pressure and destruction of CNS tissue
Headache that is worse in morning, seizures, and balance/gait/walking difficulties
How is PET used in CNS tumor diagnosis?
PET helps differentiate necrosis from malignancy by detecting areas of high metabolic activity using FDG.
How is CT used in CNS tumor diagnosis?
CT can distinguish CSF, blood, edema and tumor from normal brain tissue.
What is the role of Biopsy in CNS tumors.
Biopsy allows all areas of tumor to be studied before surgery.
What are the two major patterns of CNS tumor spread?
Local invasion and CSF seeding
What is the staging system for CNS tumors?
its not what you think, its not TNM
No standard staging system is in place.
Where do Ependymomas originate?
Ependymomas originate in the lining of the ventricles and doesn’t spread to normal brain tissue.
An ependymoma is a type of tumor that arises from ependymal cells, which line the ventricles of the brain and the central canal of the spinal cord.
.
What can Ependymomas block and what issues can that cause?
CSF
it caused the ventricles to enlarge
Ependymomas are usually an adult cancer or childhood cancer?
Childhood cancer
can be benign (non-cancerous) or malignant (cancerous)
What is Hydrocephalus
Hydrocephalus also known as “water on the brain,” is a medical condition in which there is an abnormal accumulation of CSF in the ventricles. This may cause increased intracranial pressure inside the skull and progressive enlargement of the head, convulsion, tunnel vision, and mental disability. Hydrocephalus can also cause death.
What are the most common symptoms of Spinal cord tumors?
The most common symptoms are pain and weakness along with sensory changes and sphincter dysfunction (yes, that sphincter)
Most Spinal Cord tumors originate where?
Most spinal cord tumors originate outside the Dura mater and are metastatic
What are Intradural spinal tumors?
Intradural spinal tumors are the primary lesions and are rare
Describe where the Spinal cord starts and where it extends to.
The spinal cord starts at the medulla in the brain and extends to L1/L2 in adults; it does not run the entire length of the spinal column.
Brain stem Glioma originates where?
Originates in the medulla, pons, or midbrain
What is the prognosis for Brainstem Glioma (good or bad) and why?
Overall Bad prognosis
It is difficult to biopsy due to the location
What is the most common source of brain metastases?
Lung cancer
Are Ogliodendrogliomas benign or malignant?
Ogliodendrogliomas are benign, slow-growing tumors
Ogliodendrogliomas originate where?
In the brain cells called ogliodendrocytes
Usually occur in the frontal lobe
In most cases, what is the treatment for Ogliodendrogliomas
In most cases the entire tumor can’t be removed with surgery and radiation therapy is used for residual disease
Glioblastoma multiform originates where?
It is a high grade tumor with a poor prognosis. Remember what the survival rate was?
Originates in the glial cells in the cerebrum.
survival rate is 6.9%
why do gliomas spread more aggresively?
Because they don’t form a natural capsule that inhibits growth.
