Brain Tumors - A Brief Overview
A 40-year-old male comes to the emergency room after having suffered a generalized seizure and complaining of a several month history of increasing weakness in his left arm. Both a CT scan and an MRI study reveal a tumor growing into the right front portion of the man’s brain. A 45-year-old female visits the emergency room with almost the exact same history as the gentleman described previously. She suffered a seizure of her left side involving the arm and leg and has noticed over the last year a gradually increasing numbness and weakness of her left arm and leg. A CT scan and an MRI study reveal a tumor growing from the coverings of the right side of her brain causing significant brain compression. A 5-year-old child presents to the emergency room with a three day history of nausea and vomiting accompanied by a one day history of lethargy. An urgent brain CT scan reveals enlarged ventricles, which are the fluid filled cavities of the brain. A tube is placed – on an emergency basis – into the ventricles to drain the excess fluid, and an MRI scan reveals a mass in the child’s midline cerebellum. Finally, a 60-year-old male with known lung cancer arrives at the emergency room with sudden onset of right sided weakness and speech difficulty. A CT scan reveals a possible mass in his left temporal-parietal region. An MRI scan confirms the mass and reveals two other masses in his brain.
The diagnosis of brain tumor strikes terror into the hearts of all patients. Every patient visualizes his or her imminent death in six months or less. Such a reaction is natural but is not necessarily based in reality. There are over 120 types of brain tumors ranging from the exquisitely malignant with death generally ensuing within six to ten months to the extremely benign where a watchful waiting approach is appropriate. The four examples noted above represent four patients with completely different types of brain tumors. The 40-year-old male has a glioblastoma multiforme and will be dead within a year even with the best therapy. The 45-year-old female has a benign meningioma that will be completely removed with surgery and will not recur. The child has a medulloblastoma that is amenable to a combination of surgery and chemotherapy. Finally, the gentleman with lung cancer has metastatic disease in his brain – the most common type of brain tumor. As can be seen, each patient has a different prognosis and will undergo a different type of treatment. In this article, I will provide a brief overview of some of the more common types of brain tumors. Hopefully, such a discussion will demonstrate that not all brain tumors are created equal.
In the United States approximately 35,000 new cases of patients with primary brain tumors are diagnosed each year while approximately 130,000 new cases of metastatic brain tumors are diagnosed each year. Brain tumors are the second leading cause of cancer deaths in children while metastatic brain tumors (tumors spreading from other parts of the body) are the most common types of brain tumor. In fact, 10-15% of all patients with cancer will develop brain tumors from their cancer. The most common childhood brain tumors are astrocytomas, medulloblastomas, and ependymomas. The most common adult brain tumors are metastatic tumors from lung, breast or melanoma, glioblastomas, meningiomas, and astrocytomas. Overall, however, both men and women have less than a ½% chance of dying from a brain tumor.
Brain tumors can range from highly malignant to benign; their impact on the patient depends, however, not only on their pathology but also on their location in the brain. Some types of very benign tumors cause considerable damage based upon their location of growth. In other words a meningioma is generally benign but if it is located at the base of the skull, its growth can cause significant pressure upon the brainstem or other vital structures. Symptoms from a brain tumor vary based upon the location of the tumor. The most common symptoms include headaches, seizures, weakness of one side of the body, and change in behavior. These symptoms do not mean that the patient has a brain tumor; they merely indicate the need for further studies. In this day and age, the best study to reveal a brain tumor is an enhanced brain CT scan coupled with an MRI scan. Together these will reveal almost all brain tumors. Treatment of brain tumors almost always begins with some type of surgery – at least a biopsy to obtain a piece to determine the type of tumor. Any other treatment depends upon the individual patient and tumor type. With the above in mind, let’s examine several of the more common brain tumors.
The 40-year-old male in the first paragraph had a glioblastoma multiforme or GBM. This tumor is highly malignant and patients rarely survive more than 12 months following diagnosis. When someone mentions brain cancer – this tumor is it. GBMs are included in the category of tumors known as astrocytomas. These tumors arise from the supporting cells of the brain and are generally classified using a grading system – grade I, the most benign to grade IV, a GBM, or most malignant. GBMs are the most common and most aggressive of all primary brain tumors accounting for 50-60% of all primary brain tumors. GBMs are most commonly found in males and occur in all age groups. The symptoms of a GBM depend primarily on its location in the brain. The most common symptoms include headaches, seizures and focal neurological deficits. GBMs in the frontal lobe can become quite large and present with personality changes in a patient when the tumor is advanced. On the other hand, patients with tumors in more eloquent regions can experience seizures, numbness, weakness or speech difficulties. Regardless of the patient’s first presentation, GBMs are highly invasive tumors, and tumor cells have been demonstrated in all portions of the brain even when the tumor appears to be localized to one area.
Treatment of a GBM almost always begins with surgery – either a biopsy for tissue diagnosis or a complete as possible resection of the tumor. Surgery is almost always followed by both radiation treatment and chemotherapy. In some cases, chemotherapeutic wafers are placed in the tumor bed to kill any remaining tumor cells left following surgery. Unfortunately, even following the triad of surgery, radiation and chemotherapy, the average survival is approximately 12 months. Few patients survive three years and those long-term survivors of five years may be an original misdiagnosis.
The 45-year-old female in the first paragraph had a meningioma. This tumor arises from the meninges or the covering of the brain and is generally considered to be a benign or non-cancerous tumor. Meningiomas account for approximately 25% of all brain tumors and are most commonly found in females. The tumor itself can be significantly affected by both estrogen and progestin, and growth of the tumor during pregnancy is quite common as is involution of the tumor at menopause. In fact, the tumor generally contains hormonal receptors and can be treated with hormones as one possible avenue of therapy. Meningiomas generally grow slowly, do not invade the normal brain substance, do not metastasize, can occur as multiple tumors, and generally present when the tumor reaches a fairly large size. The symptoms of a meningioma depend primarily on its location in the brain and its size. Due to the fact that meningiomas are slow growing, the brain is able to compensate for the added pressure. As a result, the most common symptoms include headaches, seizures, personality changes, and focal neurological deficits. Again, meningiomas in the frontal lobe can become quite large and present with personality changes in a patient when the tumor is advanced. On the other hand, patients with tumors in more eloquent regions can experience seizures, numbness, weakness or speech difficulties even with a small tumor.
Treatment of a meningioma in an easily reached area of the brain is complete surgical removal. In fact, surgery is the preferred method of treatment for easily accessible tumors and provides a better outcome than in any other tumor type. In some patients, a watchful waiting approach may be the treatment of choice. For those patients in whom the tumor can only be partially removed or in whom the tumor recurs, radiation treatment including stereotactic radiation can be employed as an adjuvant treatment. Hormonal therapy can also be used in selected patients while chemotherapy itself has limited use in the treatment of patients with meningiomas. Patients who undergo a complete resection of their meningioma usually experience a normal life expectancy while those with partially resected tumors or tumors in eloquent areas have life expectancies based upon the location of the tumor, tumor characteristics, and other available treatment. If you were asked to choose a brain tumor for best prognosis, the meningioma would be one of your top choices.
The 5-year-old child in the first paragraph had a medulloblastoma. This tumor is the most common malignant brain tumor in children and originates from cells in the cerebellum. Unfortunately, the medulloblastoma can be highly invasive and may even spread cells to other portions of the central nervous system by way of the cerebrospinal fluid. Many times tumor cells can be found in the lumbar region after having dropped from the cerebellum. These collections of cells are called “drop metastases or tumors.” The medulloblastoma is most common in male children but a sub-group of tumors can be found in young adults during their twenties. Patients with medulloblastomas, especially children, almost always present with nausea and vomiting due to blockage of the spinal fluid pathways. In addition, patients with medulloblastomas almost always experience headaches that are worse in the morning. Finally, based upon its location in the cerebellum, patients with medulloblastomas develop walking difficulties, and many children demonstrate a subtle than progressive decline in school accompanied by significant irritability.
Treatment for medulloblastoma begins with as complete a surgical resection of the tumor as possible. Studies have demonstrated that the greater the surgical resection of tumor the better the prognosis for the patient. Following surgery, most patients receive a combination of radiation therapy and chemotherapy. Due to the tumors ability to spread through the spinal fluid, the entire brain and spine are usually included in the radiation therapy. Finally, due to the fact that radiation causes significant problems with growth and development, most children under the age of three do not receive radiation therapy but undergo chemotherapy alone as the sole adjuvant treatment. If the tumor recurs, further surgery and chemotherapy can be instituted.
Metastatic brain tumors
The 60-year-old gentleman with known lung cancer in the first paragraph suffered from metastatic brain tumors. Brain metastases are not only the most common complication of cancer but are also the most common brain tumor encountered in the adult population. These tumors begin as cells from the main cancer mass that break off and migrate through the blood stream until they lodge in the smallest end blood vessels of the brain. The most common type of metastatic tumors originate from lung, breast, colon, and melanoma tumors. Metastatic brain tumors can be the first indication of cancer in the body or they can appear years after the primary tumor has been discovered and treated, such as commonly occurs with melanoma and breast cancers. Symptoms of a metastatic brain tumor are much like those of other brain tumors and are based upon location, number and size of tumor. Headaches, nausea, vomiting, confusion, neurological deficits and seizures are some of the most common symptoms of patients with metastatic tumors in the brain. The diagnosis of these tumors should be undertaken using a contrast-enhanced MRI scan so as to demonstrate any and all of the tumors. The MRI may detect tumors as small as ¼ inch.
Treatment of metastatic brain tumors generally depends upon number, type and location. If only one tumor is present, surgical removal followed by radiation therapy would be the treatment of choice. Patients with multiple tumors generally undergo whole-brain radiation. Some patients may be candidates for stereotactic radiation. Finally, chemotherapy can be tailored to the individual patient and his or her primary cancer. Prognosis for these patients depends primarily on the type of tumor and number of tumors present. Some patients succumb to their primary tumors first while others have a significantly longer life expectancy.
The medicolegal aspects of brain tumors
Generally, the two areas involved in legal issues are the failure to diagnose a brain tumor and the surgical removal of a tumor coupled with appropriate adjuvant treatment. Inasmuch as earlier diagnosis and treatment affects prognosis of patients with most brain tumors, the clinician must be vigilant in diagnosing patients with brain tumors. This includes the liberal use of brain CT and MRI scanning – both non-invasive, easily obtained testing. Moreover, early appropriate treatment must be instituted promptly and in the most efficacious manner. Finally, referral to a specialist is a must especially for those patients who will require specialized adjuvant treatments such as chemotherapy or radiation therapy. Failure to do any of those actions could be construed as medical malpractice, depending on the exact circumstances of the individual case.
The diagnosis of “Brain Tumor” is generally frightening to the patient and invokes visions of an early death. Unfortunately, for certain types of tumor, such a fear is reality; on the other hand, many types of brain tumors can be and generally are treated effectively such that the patient enjoys an almost normal life and life expectancy. A multitude of advances in treatment have occurred over the past decade especially with regard to the care and treatment of patients with medulloblastomas, meningiomas, and metastatic tumors. Patients with these tumors have experienced both an improved life expectancy and an improved quality of life. Unfortunately, patients with GBMs have not benefited from any such medical breakthroughs. Hopefully, this overview has served as a quick reference on brain tumors and provided realistic insights into the different types of brain tumors discussed.
- Central Brain Tumor Registry of the United States (CBTRUS) www.cbtrus.org.
- Wilkins RH, Rengachary SS eds: Neurosurgery McGraw-Hill, New York, New York, 1996.
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