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)