Neuro-Oncology
CH 4: NEUROPSYCHOLOGICAL PROBLEMS IN NEURO-
ONCOLOGY
Introduction and History:
1. Neuropsychological studies in the field of oncology are related to
neuro-oncology:
- Brain tumors = arise from neurons and other brain tissue, cranial
nerves, leptomeninges, neuroendocrine glands, skull, and blood
vessels
- Treatment effects
2. 1800s = movement that integrated neurology and psychiatry
- More direct associations of psychological behaviors with brain
masses
- Psychiatric disturbances = thought to be the result of cerebral
tumor if primary and secondary effects of the tumor were global
- Localizationist movement in late 1800s
- Beginning of surgical resection of tumors with beneficial effects
on behavior
Frequency of CNS Tumors:
1. Only 20% diagnosed before age 20
2. Second most common malignancy and account for 20% of all
childhood cancers
Diagnosis of Brain Neoplasms:
1. Risks for developing a brain tumor:
- Usually, a brain tumor is found incidentally after a fall or accident
- Risks include:
o Serious head injuries decades before tumor is diagnosed (=
meningioma)
o Prior radiation exposure decades before diagnosis
o Immune suppression leading to symptoms
, o Genetic disorders
o Environmental changes and viruses
2. Tumor grading:
- Currently, four-level system decided by the American Joint
Commission on Cancer
- Previously, three-level system by WHO
- Grading system:
o Determines degree of malignancy of the tumor
o Classifies cells in terms of abnormal features (= informs
prognosis and treatment options)
o In general, brain tumor types are graded by:
how abnormal the cancer cells and nuclei appears
Direct observation of mitosis in genetic markers (=
indicates likelihood the tumor will grow or
disseminate)
- Tumor grading = used for the most common tumors (=
gliomas); a general classification is:
o Well differentiated and low grade
o Moderately differentiated and intermediate
o Poorly differentiated and high grade
o Undifferentiated and high grade
- Gliomas are classified as:
o Low grade/I = tumor cells remain well differentiated and
without other signs of abnormality in cell nucleus or tissue
structure
Tumor cells grow slowly, rarely grow into surrounding
tissue, and may be gross totally resected
o Low grade/II = moderately differentiated but still benign
Greater chance of de-differentiation and
transformation into more malignant tumor
May have spread into surrounding tissue
, o Anaplastic/III = poorly differentiated; likely to spread into
secondary tissue; tumor is malignant
o IV = high grade, undifferentiated, highly malignant and
aggressive tumor; e.g., glioblastoma
Neuropsychological Mechanisms:
1. Tumor grade = related to severity of neuropsychological deficit
- Disrupt neural connectivity even if low-grade
2. Cognitive dysfunction = WM, attentional dysregulation, memory
encoding and retrieval, slowed info processing
3. Can also cause syndromes = aphasia, amnesia, dyspraxia,
executive dysfunction
4. Effects of tumors on cognitive function:
- Cause less functional damage than other more rapidly acquired
brain injuries
- Can appear as dementia or psychiatric syndromes
- Damage normal tissue by compression and infiltration
o Related biochemical causes:
Herniation, edema, seizure genesis, and obstruction
of interventricular CSF (= with resulting
hydrocephalus)
- Surgical techniques:
o Attempt to limit the resection within the confines of the
tumor lesions
o Spare normal-appearing cortex and subcortical white
matter
- Tumors can infiltrate but usually cannot destroy tissue (= allow
for some neural function)
- Cause loss or displacement of white fiber tracts
5. Regional cognitive effects:
- Pattern of hemispheric specialization:
o Right cerebellar tumors result in greater linguistic and
sequential processing dysfunction
, o Left hemisphere tumors result in greater visuospatial
impairment
- Variability among patients due to tumor effects on cognition
being less severe
6. Regional effects in individuals:
- Slow growth of tumor = moderates the interference with
cognitive dysfunction
o May be followed by reduced cognitive recovery
- Stability or slow decline in specific cognitive functions over time
- Non-progressive tumors = rarely generalized decline in cognition
under treatment
- Stable tumor = relative stability of cognitive functions can be
very disturbed following resection
o Significant improvement for 1-2 years after resection (=
involves morphologic adjustment and neural plasticity)
o Subjective improvement in function
7. Individualized approach to neuropsych evaluation:
- Needed due to the diffuse nature of tumors
- It is a sensitive approach
- Effective in predicting tumor growth and can predict tumor
recurrence
8. Neurosurgery effects on cognitive function:
- Tumor effects on sensation, motor function, and cognition can be
exacerbated following surgical resection; new deficits may
emerge
- Surgical resection:
o Sudden onset disruptions in speech, motor function,
cognition and affect immediately after resection
o Improvement in cognition, personality, or mood (= related
to alleviation of mass effects)
- Cognitive function takes up to 2 years, at least, for recovery
Syndromal Neuropsychiatric Disturbances and Treatments: