Brain Cancer Medical Students PDF

Brain Cancers: OUTLINE  DEFINITION  EPIDERMIOLOGY  AETIOLOGY/RISK FACTORS  ANATOMY  PATHOLOGY/PATHOPHYSIOLOGY  STAGING  CLINICAL PRESENTATION  TREATMENT/ PROGNOSIS.  Primary brain tumors are those tumors that start in the brain.  described as low grade or high grade.  A low-g...

Brain Cancers: OUTLINE  DEFINITION  EPIDERMIOLOGY  AETIOLOGY/RISK FACTORS  ANATOMY  PATHOLOGY/PATHOPHYSIOLOGY  STAGING  CLINICAL PRESENTATION  TREATMENT/ PROGNOSIS.  Primary brain tumors are those tumors that start in the brain.  described as low grade or high grade.  A low-grade tumors grows slowly, but can transform into high-grade tumor.  A high-grade tumor usually grow faster.  Secondary brain tumors, also called brain metastases, are much more common than primary tumors. They spread from other parts of the body, such as the breast, lung, colon.  cancer spread to the meninges and the cerebrospinal fluid (CSF), it is called leptomeningeal metastases or neoplastic meningitis. EPIDERMIOLOGY  Brain and other nervous system cancer is the 10th leading cause of death for men and women  Age. Brain tumors are more common in children and older adults.  Gender. men are more likely than women to develop a brain tumor.  Home and work exposures. Exposure to solvents, pesticides, oil products, rubber, or vinyl chloride.  Family history. About 5% of brain tumors may be linked to hereditary genetic factors or conditions, including Li-Fraulein syndrome, neurotransmitters, devoid basal cell carcinoma syndrome, tuberous sclerosis, Turbot syndrome, and von Hippel-Lindau disease. AETIOLOGY/RISK FACTORS  Exposure to infections, viruses, and allergens. Infection with the Epstein-Barr virus (EBV) increases the risk of CNS lymphoma., high levels of cytomegalovirus (CMV)  Electromagnetic fields such as energy from power lines or from cell phone use, show no link to an increased risk of developing a brain tumor in adults. Because of conflicting information regarding risk in children, the World Health Organization (WHO) recommends limiting cell phone use and promotes the use of a hands-free headset for both adults and children.  Race and ethnicity. In the United States, white people are more likely to develop gliomas but meningioma is commoner in black people.  Ionizing radiation. Previous treatment to the brain or head with ionizing radiation, including x- rays  Head injury and seizures  N-nitroso compounds. Some studies of diet and vitamin supplementation seem to indicate that dietary N-nitroso compounds may raise the risk of both childhood and adult brain tumors. Dietary N-nitroso compounds are formed in the body from nitrites or nitrates found in some cured meats, cigarette smoke, and cosmetics. ANATOMY  3 main parts: the cerebrum, the cerebellum, and the brain stem. The meninges, which surround the brain, are also considered part of the brain.  The cerebrum. the largest part of the brain. 2 cerebral hemispheres on either side of the brain. It is divided into 4 lobes where specific functions occur:  The frontal lobe controls reasoning, emotions, problem-solving, expressive speech, and movement  The parietal lobe controls the sensations of touch, such as pressure, pain, and temperature. also controls parts of speech, visual-spatial orientation, and calculation  The temporal lobe controls memory, special senses such as hearing, and the ability to understand spoken or written words  The occipital lobe controls vision  The cerebellum. located at the back part of the brain  responsible for coordination and balance  The brain stem: connects to the spinal cord and the cerebellum.  controls involuntary functions : heart beats, breathing.  The meninges. These are the membranes that surround and protect the brain and spinal cord.  3 meningeal layers: the dura mater, arachnoid, and pia mater.  The cerebrospinal fluid (CSF) is made near the center of the brain, in the lateral ventricles. CSF circulates around the brain and spinal cord between the arachnoid and pia layers.  Blood supply of the brain and spinal cord depends on two sets of branches from the dorsal aorta.  The vertebral arteries arise from the subclavian arteries  the internal carotid arteries are branches of the common carotid arteries.  The vertebral arteries and the ten medullary arteries that arise from segmental branches of the aorta provide the primary vascularization of the spinal cord  Venous drainage thru dura sinouses - internal jugular  Blood brain barrier PATHOLOGY/ PATHOPHYSIOLOGY  Gliomas are one of the most common types of brain tumors.  grow from glial cells or glial precursor cells, a type of supportive cell in the brain.  Other types of supportive cells in the brain include astrocytes, oligodendrocytes, and ependymal cells.  Gliomas may be considered astrocytoma, oligodendroglioma, or ependymoma.  Gliomas are assigned a grade, indicating the aggressivenes of the tumor.  Astrocytoma. Astrocytoma is the most common type of glioma. Astrocytoma cells look like glial cells called astrocytes that are found in the cerebrum or cerebellum. There are 4 grades of astrocytoma.  Grade I or pilocytic astrocytoma is a slow-growing tumor , mostly benign. Astrocytoma occur more in children than adults.  Grade II or low-grade diffuse astrocytoma is a slow-growing tumor that can often spread into nearby tissue and is of higher grade.  Grade III or anaplastic astrocytoma is a cancerous tumor that can quickly grow and spread to nearby tissues.  Grade IV or glioblastoma is a very aggressive form of astrocytoma.  Oligodendroglioma arise from glial cells called oligodendrocytes.  These cells are responsible for making myelin.  Myelin surrounds the nerves and is rich in protein and fatty substances called lipids. They are subclassified as either oligodendroglioma, which is considered low grade, or anaplastic oligodendroglioma.  Ependymoma. they occur more often in the spine. Close relationship with CSF pathways  Brain stem glioma.  begins in the glial cells in the brain stem  Non-glioma tumors: tumors that arise from cells in the brain that are not glial cells.  Meningioma. Meningioma is the most common primary brain tumor. It begins in the meninges and is most often noncancerous. Meningioma can cause serious symptoms if it grows and presses on the brain or spinal cord or grows into the brain tissue.  Pineal gland and pituitary gland tumors. These are tumors that start in the pineal gland and pituitary gland.  Primary CNS lymphoma. This is a form of lymphoma. Lymphoma is a cancer that begins in the lymphatic system. Primary CNS lymphoma starts in the brain and can spread to the spinal fluid and eyes.  Medulloblastoma is thought to start from the cerebellar granule progenitor cells. It is most common in children and is usually cancerous, often spreading throughout the CNS.  Craniopharyngioma. Craniopharyngioma is a benign tumor that begins near the pituitary gland. These tumors are rare.  Schwannoma is a rare tumor that begins in the nerve sheath. It may often occur in the vestibular nerve in the inner ear that helps control balance, noncancerous. CLINICAL PRESENTATION  Headaches, which may be severe and worsen with activity or in the early morning  Seizures.  Change in sensation, vision, smell, and/or hearing  Complex partial  loss of awareness or a partial or total loss of consciousness  repetitive, unintentional movements, such as twitching  Personality or memory changes, Nausea or vomiting, Fatigue, Drowsiness, Sleep problems, Memory problems  Loss of balance and difficulty with fine motor skills  Partial or complete loss of vision is caused by a tumor in the occipital lobe or temporal lobe of the cerebrum.  Changes in speech, hearing, memory, or emotional state.  Lactation, altered menstrual periods in women,growth in hands and feet in adults: pituitary tumor.  Vision changes, including loss of part of the vision or double vision: tumor in temporal lobe, occipital lobe, or brain stem. Diagnosis  MRI  Tissue sampling/biopsy/surgical removal of a tumor.  CT scan  Positron emission tomography (PET) or PET-CT scan.(Hallmark cos it offers both structural and functional pathology)  Lumbar puncture or spinal tap.  Myelogram  Molecular testing of the tumor. Treatment  Treatment options and recommendations depend on several factors:  The size, type, and grade of the tumor  Pressure symptoms on vital parts of the brain  spread to other parts of the CNS or body  Possible side effects  The patient’s preferences and overall health.  TREATMENT  Surgery: craniotomy, excision  Chemotherapy: with drugs that cross the BBB: lomustine (Gleostine), procarbazine (Matulane), and vincristine (Vincasar), temozolamide  Radiotherapy: adjuvant or curative or even palliative  Monoclonal antibodies/ targeted therapy: Lapatinib (Tykerb) may be used for HER2-positive breast cancer , bevacizumab (anti VEGF) Radiation therapy  Conventional radiation therapy. whole brain radiation therapy for brain metastases.  3-dimensional conformal radiation therapy (3D-CRT). Using images from CT and MRI scans , radiation beams directly at the tumor, sparing the healthy tissue from high doses of radiation therapy.  Intensity modulated radiation therapy (IMRT). IMRT is a type of 3D-CRT , that can more directly target a tumor. It can deliver higher doses of radiation to the tumor while giving less to the surrounding healthy tissue.  Proton therapy. Proton therapy is a type of external-beam radiation therapy that uses protons rather than x-rays. At high energy, protons can destroy tumor cells.  Stereotactic radiosurgery. Stereotactic radiosurgery is the use of a single, high dose of radiation given directly to the tumor and not healthy tissue.  A cyber knife is a robotic device used in radiation therapy to guide radiation to the tumor, particularly in the brain, head, and neck regions. References:  Medscape  NCCN guidelines 2018  QUESTIONS