Brain Cancer Pathophysiology and Types

Study Notes

Brain cancer affects both adults and children, but the disease manifests differently in each.
Children generally have better outcomes than adults, with a 74% 5-year survival rate compared to 21% for adults over 40.
Cancers can be malignant or benign, and both can be fatal.
Brain cancer is more common in men than women.
In the US, white people are more likely to develop gliomas and less likely to develop meningiomas compared to black people. People from northern Europe are more than twice more likely to develop brain tumors than those in Japan.
The cause of brain cancer is unknown.
Exposure to ionizing radiation during treatment can increase the risk of brain cancer.

Gliomas are the most common type, starting in the glial cells (neuroglia).
- Astrocytoma is the most common type of glioma, starting in astrocytes.
- Ependymoma starts in ependymal cells, more common in children.
- Glioblastoma Multiforme (GBM) is a high-grade astrocytoma.
- Oligodendrogliomas and oligoastrocytomas come from oligodendrocytes.
Non-glioma tumors include:
- Medulloblastoma: High-grade tumor that begins in the cerebellum; more common in children.
- Meningioma: Usually benign, slow-growing tumors starting in the membranes covering the brain/spinal cord (meninges), common in adults.
- Pituitary tumors: Usually benign, start in the pituitary gland, common in adults.
- Schwannoma: Begins in Schwann cells, which surround nerves in the brain.
Lipoma (most commonly in the corpus callosum)

Symptoms depend on tumor location in the brain.
General symptoms can include pressure on the skull.
Frontal lobe symptoms include planning/organising challenges, behavioral/personality changes, depression, difficulty walking, difficulty locating objects, speech/sight problems.
Parietal lobe symptoms include difficulty with reading/writing, loss of feeling in parts of the body, difficulty with spatial awareness.
Occipital lobe symptoms include vision loss (partial or complete).
Temporal lobe symptoms include trouble remembering, difficulty understanding, forgetting events and conversations.
Symptoms from pituitary gland include headaches; trouble with vision; nausea/vomiting; problems with hormone levels (thyroid).
Cerebellum involvement causes coordination/balance issues, uncontrolled eye movement, stiff neck, feeling dizzy
Brain stem involvement results in coordination problems, swallowing/speech difficulties, double vision, problems with facial nerves, weakness.
Spinal cord involvement results in back/neck pain, numbness, tingling, muscle tone changes, loss of bowel/bladder control

History taking, physical examination, and neurologic examination (testing cranial nerves, reflexes, sensory/motor function) are used.
Direct visualization techniques like brain scans (CT/MRI), X-rays, cerebral angiography, and PET scans help detect tumors.

Grade I (low-grade): Tumor cells resemble normal cells, slow growth that rarely spreads to nearby tissues, often curable with surgery.
Grade II: Tumor cells grow and spread more slowly than grades III and IV, may spread to nearby tissues, some tumors may become higher-grade.
Grade III: Tumor cells look different from normal, grow quickly, and tend to spread to nearby tissues.
Grade IV (high-grade): Tumor cells look abnormal and grow/spread very quickly, there is often areas of dead cells within the tumor, usually not curable.

Treatment varies based on location, extent, and nature of the tumor(s).
For primary brain tumors: surgical resection (complete or partial removal) is the main approach, aiming to remove the tumor completely and preserve neurologic function.
Radiation therapy is often used along/after surgery, using high-energy beams to kill cancer cells, often used precisely in stereotactic radiosurgery for small tumors.
Chemotherapy involves using drugs to kill cancer cells; it can be taken orally, or intravenously.
Other treatments include anti-swelling medication (steroids), and anti-seizure medication (anticonvulsants).
Side-effects of treatment are considered and managed along with rehabilitation, if necessary.