Tumors are grouped by their abnormalities. Glioblastoma gets the highest grade in its family — grade IV — in part because of its high growth rate. These cancers can grow 1. The growth is happening on a microscopic level, but a glioblastoma tumor can double in size within seven weeks median time.
The fastest growing lung cancers, by comparison, have a median doubling time of 14 weeks. These cancer-made blood vessels can be poorly built and lead to blood clots.
Fewer than two percent of glioblastomas travel — or metastasize — outside the brain. You may be wondering: If new blood vessels are the root of these problems, why not use chemotherapeutic drugs to curb their growth?
The answer is cancer stem cells. Glioblastoma tumors make their own stem cells, with multiple avenues through which they can cultivate blood vessels — like a farmer that grows more than one crop. Shut down one road to making blood vessels, which doctors have done , and the cancer stem cells will simply switch to another.
Glioblastomas — like all cancers — are spawned by gene mutations, which accumulate naturally over a lifetime. Many chemotherapy treatments target these mutations as a way to identify and kill off cancer cells. But glioblastoma quickly develop ways to reverse the effects of many chemotherapeutic drugs — hence why even when doctors remove a tumor and follow aggressively with chemo, glioblastomas recur 90 percent of the time.
This same pool of developing cells splits off to form astrocytes for the brain. John McCain was just diagnosed with glioblastoma. What do we know about this type of cancer? William Brangham speaks with Cedars-Sinai's Dr. John Yu. Tumors are graded on a scale from 1 to 4 based on how different they look from normal cells.
The grade indicates how fast the tumor is likely to grow and spread. A grade 4 tumor is the most aggressive and fastest-growing type. It can spread throughout your brain very quickly.
Glioblastomas often grow in the frontal and temporal lobes of the brain. They can also be found in the brain stem, cerebellum, other parts of the brain, and the spinal cord.
The median survival time with glioblastoma is 15 to 16 months in people who get surgery, chemotherapy, and radiation treatment. Median means half of all patients with this tumor survive to this length of time. Everyone with glioblastoma is different. Children with higher-grade tumors tend to survive longer than adults.
About 25 percent of kids who have this tumor live for five years or more. New treatments are extending life expectancy even more. People whose tumors have a favorable genetic marker called MGMT methylation have better survival rates. MGMT is a gene that repairs damaged cells. When chemotherapy kills glioblastoma cells, MGMT fixes them. MGMT methylation prevents this repair and ensures that more tumor cells are killed. Glioblastoma can be hard to treat.
It grows quickly, and it has finger-like projections into the normal brain that are hard to remove with surgery. These tumors also contain many different types of cells.
Some treatments may work well on some cells, but not on others. If these and other treatments are approved, they could one day improve the outlook for people with glioblastoma. Like other cancers, it starts when cells begin to grow uncontrollably and form tumors. So you could end up with the disease on both sides of your brain — or really at any location in the brain.
Bagley continued. Aside from complex neurosurgery, the gold-standard treatment approach in the fight against aggressive brain tumors involves a combination of chemotherapy and radiation therapy. Those treatment methods are the most capable of damaging tumor DNA.
Suffice it to say, making headway in the fight against glioblastoma means developing treatment methods that target and destroy cancer stem cells. Immunotherapy, which is being pioneered here at Penn under the leadership of Donald M. Desai, MD , is a beacon of hope in the fight against glioblastoma.
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