Glioblastoma Multiforme, the Brain Cancer Killer, Statistics and Current Therapies

Glioblastoma multiforme (GBM) is one of 150 recorded brain tumors (Bellenir, 2007), accounting for 78% of 18,500 cases of all malignant central nervous system cancers (Choudhury et al, 2005). Unfortunately, it is the most invasive, malignant, highly vascularized, infiltrative, and lethal glial tumor (Choudhury et al, 2010) with a poor prognosis. (Bellenir, 2007) The World Health Organization categorizes glioblastoma to be a high-grade (IV) fast growing astrocytoma containing dead tumor cells, developing in the cerebrum, especially in the frontal and temporal lobes. (Bellenir, 2007) The median age of diagnosis for glioblastoma is 50 to 70 and it is more prevalent in men than women.

 

 

Glioblastoma multiforme is characterized by differentiated cells with multinuclei in the presence of nuclear atypia, mitoses, microvascular proliferation, and pseduopalisading necrosis (Chodhurey et al, 2005).

 

Glioblastoma multiforme has two mechanisms of development. It may develop de novo (primary development), or it can originate from low-grade astrocytomas (secondary development). Primary tumors can be classified as glial or non-glial functioning as either benign or malignant. (Bellenir, 2007) An adult diagnosed with a primary tumor will only live for six months. The primary tumor over expresses the epidermal growth factor, mutation in the phosphatase and tension homolog on the chromosome, and deletions of the cyclin-dependent kinase inhibitor 2A.  (Chodhurey et al, 2005)

 

Unlike primary tumors, secondary tumors are more common in children. The secondary tumors will contain mutation in the tumor protein 53 (TP53) and over expresses the platelet derived growth factor (PDGFR).

 

Current therapies for glioblastoma multiforme include surgery, radiation, and chemotherapy. Decisions as to what treatments are used are based on the specific condition of the patient. (Bellenir et al, 2007)

 

In surgery, the neurosurgeon’s challenge is to remove as much of the brain tumor as possible. Common procedures include craniotomy and sterotactic biopsy. However, even if 90% of the tumor is removed a patient will only live for 9-15 months. Because glioblastoma is a high-grade glioma, it forms tentacle like structures that invade surrounding tissue, making surgery a less likely option. (Bellenir et al, 2007)

 

If surgery is not an option, radiation, the use of high-energy x-ray to kill cancer cells, can be used. The main types of radiation include standard external beam radiotherapy, proton beam treatment, and sterotactic radiosurgery. (Bellenir et al, 2007)

 

The final treatment, chemotherapy only positively effects 20 percent of all patients. Chemotherapy functions by causing cell damage that is better repaired by normal tissue than tumor tissue. Resistance occurs if the tumor tissue survives, and it is unable to respond to the drug. Resistance may also occur, if the drug is unable to pass through the blood brain barrier. (Bellenir et al, 2007)