Glioma vs Glioblastoma
Introduction:
Brain tumor is the most complex cancer of all due to its location in the most complex organ, the brain. Glioma and Glioblastoma are two different types of brain tumors. These tumors arise from the brain tissue and tend to usually occur in the fifth or sixth decade of life. They are also called primary brain tumors, that is, not secondary to any other cancer in the body and are the most commonly occurring as compared to other brain tumors.
Difference in origin:
Glioma accounts for 80% of the brain tumors and arises from glial cells, a type of supporting tissue for the brain cells. It is differentiated into three main groups according to the types of cells that it shares features with. A glioma could be arising from astrocytes (star shaped cells conducting brain activity), oligodendrocytes (forming protective layer around nerve cells) or ependymal cells (lining walls of fluid spaces within the brain). This also differentiates it into low grade or benign glioma and a high grade or malignant (cancerous) glioma. 30% of these gliomas are malignant.
Glioblastoma is the commonest of all malignant tumors of the brain. In fact, it is found to be highly cancerous containing a very high blood supply and comprising of dead tissue and cystic tissue. Due to its multiple forms, it is also termed Glioblastoma multiforme (GBM). It arises from star shaped cells in the brain called astrocytes. The grade IV type of tumor arising from these astrocytes which is infiltrative and undifferentiated from other normal cells is called Glioblastoma.
Difference in manifestation:
The symptoms of a brain tumor arise from increased intracranial pressure due to the increasing size of the tumor pressing on the surrounding normal brain tissue. A glioma presents with headache, nausea, vomiting, seizures or a cranial nerve disorder depending on the nerve being compressed. Its location in the spinal cord will produce symptoms like pain, weakness and numbness of the extremities.
Glioblastoma also produces headache, nausea, vomiting. According to its location in the brain it may also give rise to hemi paresis (weakness of one half of the body), seizures, memory or speech impairment and visual changes. It is found to be more common in males than females.
Difference in prognosis:
Glioma though is a slowly progressing tumor; its prognosis is not very good. There is no cure and the only aim of treatment is to bring down its growth and to manage symptoms. The survival rate from the time of diagnosis is on an average 12 months but with better modalities of treatment coming up a median survival of up to 11 to 12 years seen. Again the life expectancy depends on whether the tumor is benign or malignant with the latter carrying lesser years of survival.
Glioblastoma is a rapidly growing tumor with a survival rate of 3 to 5 months from the time of diagnosis if left untreated. But, following surgical removal a survival rate of 1 – 2 years has been observed. The years of survival reduce with increasing age. In 10% of the cases a survival rate of 5 years has also been seen.
Summary:
It can be concluded that both Glioma and Glioblastoma are common brain tumors. Their occurrence increases with progressing age and are best treated with surgical removal after being diagnosed with the help of a CT scan or a MRI scan. The surgery is followed by radiotherapy and chemotherapy to limit the growth of these tumors and to manage the symptoms arising from them. Glioblastomas arise from star shaped astrocytes while gliomas arise from any of the supportive tissue cells of the brain.