Glioblastoma often starts with a headache that will not go away. Nausea, vomiting, seizures and personality changes can follow, and symptoms usually build over days or weeks rather than months. Doctors then order an MRI or CT scan. Only a biopsy of the tumor confirms the diagnosis.
By then, the disease is already moving. Glioblastoma, once called glioblastoma multiforme, is the most common and most aggressive cancer to begin in the brain. It is a grade 4 glioma, the highest grade, and it arises from astrocytes, a type of glial cell. It makes up about 15 percent of all brain tumors, and it is the second most common brain tumor after meningioma. Roughly 3 in 100,000 people develop it each year, and the average age at diagnosis is 64.
Why it is so hard to treat
The tumor grows quickly and pushes into healthy tissue, often along white-matter tracts and blood vessels. Surgeons cannot take out every cell. Glioblastoma cancer stem cells, found in these tumors, appear to resist radiation and chemotherapy, and together with the tumor’s diffuse spread they are thought to explain the high rate of recurrence.
Standard care has a familiar order. Surgery removes as much of the tumor as is safe, then radiation and chemotherapy follow, usually with temozolomide. Complete removal gives a better outlook than partial removal, but even so the cancer almost always returns, and surgery adds only some months of survival. Clinical trial participation is preferred under current NCCN guidelines when one is available.
The numbers are hard. Cleveland Clinic puts average survival at 15 months after diagnosis, and less without treatment. Other estimates run lower, at 10 to 13 months with treatment and about three months without. Fewer than 10 percent of patients are alive at five years. There is no cure.
What causes it
For most people, nobody knows. The mutations behind glioblastoma usually happen at random during a lifetime. About 5 percent of cases come from hereditary syndromes such as neurofibromatosis and Li-Fraumeni syndrome. Previous radiation therapy is a risk factor, and the tumor appears more often in men for reasons that are unclear. No method of prevention is known.
Cleveland Clinic notes that survival figures are estimates built on past patients and do not account for what new treatments and clinical trials may change. Its advice is to lean on the care team, consider a support group, and ask about genetic testing if brain tumors run in the family. Anyone with symptoms that fit should see a doctor promptly, and patients should talk to their doctor about every treatment option, including trials.
