CNS
TD 5/5 Lens
1/3V: 10Gy 2/3V: 10Gy 3/3V: 10 Gy Endpoint: Cataract
TD 5/5 Lacrimal Gland
1/3V: 26Gy 2/3V: 26Gy 3/3V: 26Gy Endpoint: Dry Eye
TD 5/5 Ear
1/3V: 30Gy 2/3V: 30Gy 3/3V: 30Gy Endpoint: Acute Serous Otitis 1/3V: 55Gy 2/3V: 55Gy 3/3V: 55Gy Endpoint: Chronic Serous Otitis
TD 5/5 Parotid
1/3V: 32Gy 2/3V: 32Gy 3/3V: 32Gy Endpoint: Xerostomia
TD 5/5 Spinal Cord
1/3V: 50Gy 2/3V: 50Gy 3/3V: 47Gy Endpoint: Myelitis/Necrosis
TD 5/5 Optic Chiasm
1/3V: 50Gy 2/3V: 50Gy 3/3V: 50Gy Endpoint: Blindness
TD 5/5 Optic Nerve
1/3V: 50Gy 2/3V: 50Gy 3/3V: 50Gy Endpoint: Blindness
TD 5/5 Brain
1/3V: 58Gy 2/3V: 51Gy 3/3V: 47Gy Endpoint: Necrosis/Infarction
TD 5/5 Brain Stem
1/3V: 60Gy 2/3V: 53Gy 3/3V: 50Gy Endpoint: Necrosis/Infarction
Primary Gliomas: Survival Rate
19%-35%
CNS Tumors: Epidemiology
20,500 - 23,770 new cases annually - 13,350 in males and 10,420 in females * 1 in 140 for a man and 1 in 180 for a woman Primary tumors represent <2% of all cancers in the US Approximately 14,000 - 16,050 people will die from CNS tumors - 9,440 males and 6,610 females Approximately 3 out of 10 of all brain tumors are gliomas and they are fast-growing Glioblastoma multiforme/glioblastoma (GBMs): most common primary brain tumor in adults - Median survival: 8.4 months - Optimal therapy: 12 months Brain tumors are the second leading cause of cancer death in children (behind leukemia)
AVM: Location
Brain & Spine (most common) Can occur anywhere in the body
Most common type of tumors
Brain - 80% - Gliomas (3 out of 10 brain tumors) - Metastasis Spine - 20% - Most tumors of the spine are histologically benign but can cause significant damage with compression or invasion of spinal cord - Intramedullary Ependymomas & Astrocytomas - Ependymomas of the Cauda Equina - Meningiomas Gliomas are most common - GBM - most common - Astrocytomas account for 50% of all primary CNS tumors Oligodenrogliomas are often low grade. They are considered slow growing and more sensitive to treatment than other gliomas. Ependymomas account for approx. 6% of gliomas they are slow growing and the outcome improves with aggressive surgical resection. Meningiomas account for 30% of primary tumor. They have a high recurrence rate and often need other treatments in addition to surgery. Lymphomas - not common but can form in the CNS Pituitary Tumors - most commonly benign
Clinical Presentations:
Brain Signs/Symptoms: Headache Intracranial pressure (ICP) Mental status change (mood and personality) Trouble speaking Seizure Nausea and vomiting Weakness or paralysis in part of the body Changes in vision, hearing, or other senses Spine Symptoms (are more bilateral): Pain Weakness in arms and/or legs Loss of sensation Bowel and bladder control problems
Pediatric CNS
Brain and spinal cord tumors are the second most common cancers in children (after leukemia) Account for about 1 out of 4 childhood cancers. More than 4,000 central nervous system tumors are diagnosed each year in children and teens Incidence rate (number of tumors per 100,000 children) has not changed much in recent years. Boys develop these tumors slightly more often than girls. Approximately 3 out of 4 brain tumors (all types combined) survive at least 5 years after being diagnosed. Currently, no widely recommended screening tests
Pediatric CNS: Signs/Symptoms
Brain: Seizures Trouble speaking A change of mood such as depression A change in personality Weakness or paralysis in part of the body Changes in vision, hearing, or other senses Headache Nausea/vomiting Balance problems Drowsiness/coma Spinal Cord Tumors: Weakness Paralysis Numbness
Metastatic Brain Lesions: Imaging
CT MRI PET
CNS Tumors: Etiology
Cause: Unknown Risk factors: Location of tumor and grade (low-grade, malignant, or high-grade) Age (increases with age) Radiation exposure Genetics/family history Neurofibromatosis type 1 and 2 (NF1 AND NF2) Tuberous sclerosis Immune system disorders Other factors without clear scientific proof - Electromagnetic fields - Cellular telephones - Environmental factors: vinyl chloride, synthetic rubber, aspartame
Pediatric CNS: Etiology
Causes: gene changes; not fully understood Risk factors Radiation exposure Inherited/genetic conditions: - Neurofibromatosis Type 1 - Neurofibromatosis Type 2 - Tuberous sclerosis - Von Hippel-Lindau disease - Li-Fraumeni syndrome Other possible effects: - Cell phones - Aspartame - Electromagnetic fields
Field borders for CNS: Craniospinal
Cranial Port SUP: Fall off INF: include cribiform plate and temporal fossa frontally, level of C2 posteriorly POST: Fall off ANT: Fall off to cover cranium Spinal Port SUP: inferior border of WB INF: Below S2 LAT: entire vertebral bodies with 1 cm margin Cranial Boost SUP: midway between foramen magnum and vertex plus 1cm margin INF: Bottom of C1 POST: posterior clinoid ANT: behind calvrium
Late effects in children
Decreases height in vertebral bodies - Short wasted adult Secondary malignancy Alopecia Changes of cortical atrophy and basal ganglia calcifications Neurologic defects Neurocognitive defects Hearing loss
Risk factors of surgery
Deficits of motor sensory loss Poor coordination Cranial nerve dysfunction
Dose for treatment/Late effects
Dose for Brain tumors range from 45-70Gy, depends on histology Conventional fractionation used generally up to 60 Gy for many primary brain tumors 1.8-2 Gy/fx Metastatic lesions receive lower doses and shorter courses - 30 Gy over 10 fractions - 3Gy/fx Craniospinal Irradiation - Used for tumors with high risk of spread to CSF - Treats the brain and entire spinal axis with a boost to the gross tumor volume - Common treatment for medulloblastoma - Dose: 1.8 Gy/fx to 36Gy for brain and cord - Tumor bed boost to 54 Gy at 1.8 Gy/fx Whole Brain Irradiation - Irradiation via lateral portals - For brain mets from another primary - Preferred to treat any occult disease Spinal Cord Compression Irradiation - 30-40 Gy in two to four weeks - Initial fractionation: should be 3.5-4.0 Gy/fx, for three to four treatments in an attempt to maximize the response - Doses as high as 8 Gy in a single fx have been used for one to two treatments for patients with a short-term prognosis
Pediatric CNS: Types
Gliomas - Astrocytomas - Oligodendrogliomas - Ependymomas - Mixed gliomas - Brain stem gliomas Primitive neuroectodermal tumor (PNET) Craniopharyngiomas Mixed glial and neuronal tumors Choroid plexus tumors Schwannomas
Metastatic Brain Lesions: Signs/Symptoms
Headache Seizure Loss of function Hemorrhage Asymptomatic
Blood-brain barrier crossover drugs
Hinders the penetration of some substances into the brain and CFS which exists between the vascular system and brain Purpose is to protect the brain from potentially toxic compounds Drugs must be able to penetrate the blood-brain barrier Must be lipid soluble (alcohol, nicotine & heroin) - Vincristine - Carmustine
Field borders for CNS: Whole Brain Borders
INF: 0.5-1.0 cm inferior to cribiform plate, middle cranial fossa, and foramen magnum ANT: at least 3cm posterior to ipsilateral eyelid Gantry may be 5-7 degrees anterior to true lateral to spare dose to the lens
Prophylactic cranial irradiation
Incidence of brain mets in SCLC patients are as high as 50% and as high as 80% for patients surviving for 5 years Elective whole-brain irradiation decreases incidence of brain mets by 50% and provides approx. 5% 3 year overall survival of patients in remission Associated with increase in 1 year overall survival in extensive-stage patients with a response to chemotherapy 25Gy in 10fx
Metastatic Brain Lesions: Epi & Eti
Increasing incidence Estimated 100,000 -170,000 new cases annually Patient have a median survival of 3 months Risk factors: Certain cancers Breast Lung Melanoma
Brain parts/functions/structure/location
Lobes - Front - motor cortex - Parietal - sensory cortex - Occipital - visual cortex - Temporal 2 Cerebral hemispheres - Right and left 2 Cerebellar hemispheres Cranial bones, meninges, and CSF provide an outer layer of protection for the brain Ventricles are cavities that form a communication network with each other, the center canal of the spinal cord and subarachnoid space - Ventricles, canals, and subarachnoid space are filled with CSF - CSF provides buoyancy, protection, chemical stability and prevention of brain ischemia 12 Cranial nerves CNS is composed of gray and white matter Meninges - Dura mater - Arachnoid mater - Pia mater
Metastatic to Spinal Cord
Most commonly caused by metastasis to the spine Most common primary tumors: - Lung - Prostate - Breast - Lymphomas
Patterns of Spread (CNS Adult and Peds)
Most gliomas tend to spread invasively; local invasion Don't metastasize through the lymphatics Rarely metastasize outside the CNS CSF seeding* (provide the major patterns of spread for CNS tumors) Drop mets (occur via the CSF and can form secondary tumors) Secondary seeding; growing along nerve roots causing pain or spinal cord compression Lumbosacral area; most frequent site for CSF seeding Hematogenous spread is rare
Spinal Cord Compression
Most important prognostic factor is ambulation - Median survival of 8 to 9 months is ambulatory after treatment - Median survival of 1 month for non-ambulatory patients MRI: is the most informative study
Spinal cord signs/symptoms
Pain Weakness in arms and/or legs Loss of sensation Bowel and bladder control problems Spinal Cord Compression - Back and/or neck pain - Weakness - Autonomic dysfunction - Sensory loss
Most common brain metastasis/survival rate
Primary site for mets: Breast and lung Melanoma has highest percentage of brain mets Median survival of 3 months Brain tumors are the second leading cause of cancer death in children (behind leukemia)
Primary Gliomas: Incidence Rate
Primary- 42% Malignant- 78%
Field borders for CNS: Spinal Cord Compression
SUP: 3-4 cm above the cord compression INF: 3-4 cm below the cord compression LAT: Typically 7-8 cm wide, but may vary according to the lateral extend of the tumor
Spinal fluid metastasis of tumors
Some high-grade neoplasms in the brain and meninges metastasize by "seeding" into the subarachnoid and ventricular spaces and in the spinal canal, particularly in patients with recurrent tumors Tumors with a propensity for such CSF spread include - Medulloblastomas - Ependymoblastoma - Pineoblastoma - CNS lymphomas
AVM: Treatment Considerations
Surgery (treatment of choice) - Resection - For large AVMs Endovascular embolization - Less invasive than traditional surgery - Catheter is inserted into leg and fed up to brain - Embolizing agent is ejected - Blocks off blood flow to AVM Radiation - SRS - Can only use for small AVMs - Vessels clot off in 1-3 years after treatment - Up to 3 cm area w/ 1 mm margins - Single or multiple fractions - 12-25Gy (15Gy is standard)
5-year Survival: General Glioma
Survival rates for brain and spinal cord tumors vary widely, depending on the type of tumor; range 19% to 35% Low-grade astrocytoma Anaplastic astrocytoma (intermediate grade) Glioblastomas Oligodendroglioma GMB most lethal with only 2.2% survive 3 years 5-years survival primary CNS 19% to 35% 5-year survival for spinal tumors: 90%
Brain tumor prognostic factors
The most important prognostic factor for CNS tumors is the histopathological diagnosis. The cell type of the tumor is more important than the size of the tumor.
Spinal cord length/location
The spinal cord is located in the vertebral foramen Made up of 31 segments: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal Spinal cord is nearly 25cm shorter than the vertebral column Approx. 45cm in women (17 inches) Approx. 48cm in men (18 inches)
Detection and Diagnosis
There are no widely recommended tests to screen for brain and spinal cord tumors Most symptoms appear as the tumor creates ICP Imaging: - X-rays - MRI - CT - PET - Angiogram - Magnetic resonance angiography (MRA): done to look at blood vessels in the brain - Magnetic resonance spectroscopy (MRS): measure radiowaves interaction with different chemicals in the brain - Perfusion MRI: use of contrast with the amount of blood moving through different parts of the brain - Functional MRI (fMRI): newer type of MRI; looks for tiny blood flow changes Biopsy Epidural Lumbar spinal tap Mental and intellectual function status check Motor, sensory, and reflex functions evaluations* Ophthalmoscopy: check for papilledema (edema of optic disc) Labs (blood and urine)
Pediatric CNS: Imaging
X-rays MRI CT PET Angiogram Biopsy Stereotactic needle biopsy Craniotomy Lumbar puncture Bone marrow aspiration/biopsy Labs (blood and urine)
