Senator John McCain has been diagnosed with a primary glioblastoma, deemed the deadliest of all kinds of brain cancer.

The 80-year-old Arizona senator’s condition was revealed after a tissue sample was taken as surgeons removed a blood clot from above his left eye. The tumor had been completely removed, and McCain and his family are now reviewing possible treatments with his doctors at Mayo Clinic Hospital.

But how do doctors go about treating this aggressive form of cancer?

Glioblastoma Treatment Options

“The general approach is to offer patients a combination of radiation and chemotherapy as a first-line treatment,” said medical oncologist Dr. Matthias Holdhoff in a CNN report. He was not part of the team taking care of the senator.

In standard treatment, surgery will first remove as much of the tumor as possible. After weeks of recovery, there will be five to six weeks of everyday, low-dose radiation and chemotherapy sessions. The latter is expected to help render the former more effective.

Finally, a higher-dose chemotherapy will be performed, typically five days of daily chemotherapy. After three weeks of rest, there will be another five days of treatment, and care will continue for at least six months.

Prognosis, Challenges, And Hope

Glioblastomas, however, are known to be stubborn, showing up again in the same brain region where they first appeared.

The median overall survival rate for the condition, revealed radiation oncologist Dr. Raju Raval in an LA Times report, is from 14 to 16 months. This means half of glioblastoma patients may live as long or longer, while the other half are no longer around despite treatment done.

Plenty of challenges present themselves in treatment, including the tumors’ extremely fast growth and complex nature. Glioblastomas are also known to have “fingers” on the edge of the tumors, making it so difficult to remove all cancerous cells during operation.

“There is actually a lot of diversity in the cancer cells of the tumor,” said neurosurgeon Dr. Ian Dunn in an LA Times report, likening it to a “tumor in a tumor with different features and different faces.”

But researchers are eyeing new, promising glioblastoma therapies with a focus on harnessing the immune system to battle the cancer cells. A number of patient trials are ongoing.

A cap-like device, for instance, produces electric fields to fight cancer and may assist in brain tumor patients’ survival. In a study involving patients newly diagnosed with glioblastoma, researchers found that more than twice the number of patients given the therapy survived five years after getting it, along with chemotherapy.

While on rest, McCain expressed gratefulness to his doctors and confidence that “any future treatment will be effective,” according to a statement.