Amy Herbst was at her son's out-of-town baseball tournament last year when she woke up with a headache that quickly grew so bad she could barely function.
"I felt nauseous, I felt sick, and I just had to go lie down in the car," Herbst, 41, said.
"My husband came and looked and me, and he just knew. He said, 'We're going to the emergency room.'"
A CT scan showed it was the worst possible diagnosis — a glioblastoma, the deadliest form of brain tumor.
Only about 30 percent of patients with glioblastomas are still alive two years after their diagnosis, and only 10 percent live five years.
"I know the statistics are not good for a glioblastoma grade 4," Herbst told NBC News.
She's stayed away from the internet on purpose. "I haven't looked, because I don't believe I am one of those statistics," said the upbeat mother of a 12-year-old boy and a 9-year-old girl.
Herbst is hopeful because she's been trying a new type of therapy at the University of Rochester Medical Center called tumor-treating field, or TTField treatment. For 20 or more hours a day, she wears an electrode cap and a backpack called Optune that delivers an intermediate-frequency alternating electric field to her brain.
Novocure, the company that makes Optune, says the electric field stops tumor cells from dividing normally and makes them eventually commit suicide in a process called apoptosis.
A new study published Tuesday shows that patients who used the device while also getting chemotherapy lived an average of 20 months, compared to 15 months for the patients who got chemo alone. That may not sound like much, but it can make a huge difference to a patient given a sudden death sentence, and it's an average - some patients will live much longer than that.
The trial was so compelling that the researchers stopped it so that patients who weren't using the device could have a chance to try it.
The study, detailed Tuesday in the Journal of the American Medical Association, persuaded the Food and Drug Administration to approve the device in October for use in patients newly diagnosed with glioblastoma. The FDA had OK'd it in 2011, but only for advanced patients.
Herbst had undergone surgery and radiation and when she heard about the device, she asked her insurance company if she could try it. They said no.
"It cost $21,000 a month," Herbst said. "I said, okay, it wasn't meant to be."
The middle-school math coach started chemotherapy at Rochester, still hopeful.
When the FDA approval came in October, Novocure offered Herbst the treatment under a patient assistance program. "It wasn't free, but they said it would cost a maximum of $250 a month, and $250 sounds like nothing compared to $21,000," Herbst said.
So now she shaves her head every three days and wears the electrode cap day and night.
"These arrays which have, like, electric fields and on each array they have these ceramic-like discs that send these electric waves to my head," Herbst said.
Herbst cannot really feel any clear effects from the electric fields, and she can wear a wig over the cap.
"It's way better than I expected," she said. "It's been about two months now and really, the only side-effect is your skin gets a little flakey and dry in a few spots."
Right now, no tumor is visible on a magnetic resonance imaging (MRI) scan, Herbst says, but she cannot say whether it's because the tumor was surgically removed, because of radiation treatment, the chemo, or the Optune cap.
The trouble with brain tumors is it's so hard to get at them. Surgical removal requires cutting into the brain, and chemotherapy cannot easily get past the blood-brain barrier to kill any straggling tumor cells.
The TTField can do that. Like radiation, it's coming in from the outside, so it's not stopped by that blood-brain barrier mechanism inside the blood vessels of the brain. Unlike radiation, it mostly affects cells that are dividing, so it spares healthy brain cells and stops the propagating tumor cells.
That allows doctors to position the electric field over the whole brain, catching stray tumor cells before they can circulate and start making a new tumor.
For the study being reported Tuesday, Dr. Roger Stupp of the University of Zurich in Switzerland and colleagues recruited 695 patients just diagnosed with glioblastoma. Two-thirds got the standard chemo -- a drug called temozolomide -- along with Optune treatment, while a third got chemo alone.
Chemo alone stopped brain tumors from growing back for an average of four months. In patients who got the chemotherapy plus Optune, it took on average seven months for tumors to start growing again.
The main side-effects were anxiety, confusion, insomnia and headache.
Because the patients knew they were getting an extra treatment, the researchers said, it's possible there was a placebo effect. But they note that placebo effects are very uncommon in cancer treatment.
"Still, patients who only take placebos reliably live longer than those who do not," Dr. John Sampson, a neurosurgeon at Duke University, wrote in a commentary in JAMA.
But there are not many options for treating glioblastoma, which affects about 15 percent of the 23,000 Americans who get brain tumors every year.
"Successful treatments for glioblastoma are few and far between," Sampson wrote.
"This study represents the first in a decade to demonstrate an improvement in survival in this disease," he added.
Sampson is overseeing a team trying approaches that include a tetanus vaccine to boost the effects of chemotherapy.
Glioblastoma is the tumor that drove 29-year-old Brittany Maynard to choose to end her own life, in a very public and controversial way, in Oregon in 2014.
Herbst will continue her chemo treatments until June and will keep wearing her Optune cap until then. She can't go to the gym any more, but is walking daily and continuing other activities.
"I believe I am going to beat this," she said.