Glioblastoma

Glioblastoma, previously known as glioblastoma multiforme (GBM), is the most aggressive and most common type of cancer that originates in the brain, and has very poor prognosis for survival. Initial signs and symptoms of glioblastoma are nonspecific. They may include headaches, personality changes, nausea, and symptoms similar to those of a stroke. Symptoms often worsen rapidly and may progress to unconsciousness.

The cause of most cases of glioblastoma is not known. Uncommon risk factors include genetic disorders, such as neurofibromatosis and Li–Fraumeni syndrome, and previous radiation therapy. Glioblastomas represent 15% of all brain tumors. They are thought to arise from astrocytes. The diagnosis typically is made by a combination of a CT scan, MRI scan, and tissue biopsy.

There is no known method of preventing the cancer. Treatment usually involves surgery, after which chemotherapy and radiation therapy are used. The medication temozolomide is frequently used as part of chemotherapy. High-dose steroids may be used to help reduce swelling and decrease symptoms. Surgical removal (decompression) of the tumor is linked to increased survival, but only by some months.

Despite maximum treatment, the cancer almost always recurs. The typical duration of survival following diagnosis is 10–13 months, with fewer than 5–10% of people surviving longer than five years. Without treatment, survival is typically three months. It is the most common cancer that begins within the brain and the second-most common brain tumor, after meningioma, which is benign in most cases. About 3 in 100,000 people develop the disease per year. The average age at diagnosis is 64, and the disease occurs more commonly in males than females.

Tumors of the central nervous system are the 10th leading cause of death worldwide, with up to 90% being brain tumors. Glioblastoma multiforme (GBM) is derived from astrocytes and accounts for 49% of all malignant central nervous system tumors, making it the most common form of central nervous system cancer. Despite countless efforts to develop new therapies for GBM over the years, the median survival rate of GBM patients worldwide is a dismal 8 months, with radiation and chemotherapy standard-of-care treatment beginning shortly after diagnosis only improving median survival length to around 14 months and a five-year survival rate of 5-10%. Similarly, the five-year survival rate for individuals with any form of primary malignant brain tumor is only 20%. The challenges associated with successfully treating brain cancers are numerous. In the simplest terms, brain tumors often occur in areas too difficult or dangerous to surgically resect, and most drug therapeutics are incapable of crossing the blood-brain barrier in sufficient quantities to stop tumor growth. Furthermore, while stereotactic radiosurgery-based approaches have proved to be effective for ablating a variety of brain tumors visible to MRI and other neuroimaging, metastatic brain cancers maintain high recurrence rates, with GBM recurrence seemingly inevitable.