Glioblastoma - Survival Rate, Symptoms, Causes, Treatment
Glioblastoma is a term used to describe tumors that develop from astrocytes, which are star-shaped cells that form the supportive, glue-like tissue of the brain. Glioblastoma tumor cells has a large support network of blood vessels and tend to reproduce rapidly. Due to this fact, they are typically extremely cancerous or malignant.
Glioblastomas are usually located in the brain’s cerebral hemispheres. They can also affect any other part of the brain, as well as the spinal cord.
Symptoms of glioblastoma
Most of the common signs and symptoms associated with glioblastomas are usually caused due elevated pressure on the brain, which often occurs due to rapid growth of the tumors. A few common symptoms of glioblastomas are listed below:
As per the position of the tumor, affected individuals may also develop a variety of other symptoms, including:
- Speech and/or memory problems
- Weakness that affects one side of the body
- Changes or disturbances in vision
Types of glioblastoma
Glioblastomas are classified into two types, i.e., primary or de novo, and secondary.
- Primary glioblastoma tumors tend to quickly develop and result in abnormal symptoms. It is extremely aggressive and the most common type of glioblastoma.
- Secondary glioblastoma tumors have a slightly slower growth progress, and hence take longer to develop. However, they are also aggressive tumors and represent around ten percent of glioblastomas. They may start out as low-grade malignancies and later become high-grade. They generally affect individuals who are 45 years old or younger.
Causes of glioblastoma
The precise cause of glioblastomas is yet to be found. It has no genetic links, and has no known association with the intake of cured meat, smoking, or exposure to electromagnetic fields.
Glioblastomas are generally made up of a combination of different cell types. The tumors may contain calcium deposits, cystic minerals, a mixture of cells with varying grades, and blood vessels.
In most cases, glioblastomas are highly cancerous. At any given point in time, reproduction continues to occur amongst the many tumor cells. The abundant blood supply offers them ample nourishment. It is also possible to observe dead cells, particularly in the middle of the tumor.As the glioblastoma tumors arise from healthy brain cells, they find it quite easy to attack and live inside healthy brain tissue. Glioblastomas rarely metastasize or migrate to other parts of the body.
Glioblastomas represent around 60 to 75 percent of allastrocytomas and approximately 17 percent of all primary tumors of the brain. Childhood brain tumors diagnosed as glioblastomas is steady at 3 percent. Their frequency increases with age. More men get affected by glioblastomas as opposed to women.
Some risk factors which can increase the vulnerability to developing glioblastomas are as follows:
- Excessive intake of artificial sweetener aspartame which is widely prevalent in diet sodas.
- Exposure to viruses such as HHV-6,SV40, and cytomegalovirus
- Alcohol abuse
- Prolonged contact with polyvinyl chloride that is used in the construction industry, and ionizing radiation.
Treatment of glioblastoma
Glioblastomatumors consist of several different cell types, which can pose many difficulties and problems in its effective treatment. Some types of cells may elicit a good response to certain treatments, while others may remain unaffected. Hence, treatment of glioblastoma may involve a combination of many different therapies.
Glioblastoma has to be correctly diagnosed at first. Then all the additional pressure on the brain has to be alleviated as far as possible. Later, the tumors are safely removed to the extent that is possible via surgery. Glioblastomas contain thread-like tentacles and hence very difficult to fully remove. It is more so when the tumors are growing near those sections of the brain that regulate vital functions like coordination and language. Tumors which cannot be removed via surgery are treated via radiation therapy and chemotherapy, so as to slow down their growth.
Prognosis and survival rate for glioblastoma
The outlook for glioblastoma is generally reported in years of ‘median survival.’ It refers to the time during which an equal number of patients fare worse and an equal number of patients fare better.
Adults affected by anaplastic astrocytoma exhibit a median survival of about 2 to 3 years, when standard treatment is used. With simultaneous use of radiation therapy and temozolamide, median survival for adults with more aggressive glioblastoma tumors is around 14.6 months, while 2-year survival falls at 30 percent. A 2009 study has however revealed that nearly ten percent of glioblastoma patients may live for 5 years or more.The shutdown of the MGMT gene via methylation also results in better survival rates.
Children affected by high-grade tumors tend to fare better than adults. About 25 percent of affected children have a five-year survival.
It is important to note that similar biologic anomalies may not be observed across varied glioblastomas. This is one of the major reasons why different patients with similar tumors have varying prognosis, and similar treatment produces varying responses in different patients.