In the 1990s, an Israeli biophysicist wondered whether cells that were in the process of dividing might be vulnerable to damage by electromagnetic energy.
If so, then maybe electric fields could be used to disrupt the growth of cells that divide relentlessly and uncontrollably - otherwise known as cancer.
Yoram Palti began testing his hypothesis in the lab of his fledgling company, Novocure, located in his basement.
The therapy he called "tumor-treating fields" met with deep skepticism, and some experts still have doubts.
But in the fall, the U.S. Food and Drug Administration approved an ungainly apparatus, built on Palti's work, that is the first treatment in a decade to show an improvement in survival for glioblastoma, the ferociously aggressive brain cancer.
Novocure's "Optune" is an adhesive cap with electric transducers that patients wear on shaved heads at least 18 hours a day. They also tote a six-pound generator in a backpack or shoulder bag.
The FDA approval was based on an international study, published last month in the Journal of the American Medical Association (JAMA), that found patients who wore Optune and took the chemotherapy Temodar lived a median of five months longer than those on Temodar alone. Five months isn't a lot, but it's not trivial for patients with a median survival rate of less than 15 months.
At two years, 43 percent of the Optune group were alive, compared to 29 percent with Temodar alone.
And some patients, such as Michael Coleman, 46, of Lock Haven, Pa., have defied all odds. More than four years ago, his unsuspected tumor ruptured, almost killing him. Now, his brain scans are clear.
"People ask me, 'Is that thing on your head for a sleep study or for a seizure disorder?' " said the wine store manager. "I say, 'I have brain cancer.' They say they're sorry. But I feel lucky."
In the U.S., about 12,500 people are diagnosed with glioblastoma annually. With optimal therapy - surgery, radiation, chemotherapy, and in many cases, the targeted drug Avastin - five-year survival hovers around 5 percent.
One new hope is immunotherapy, which unleashes the body's immune system to attack brain cells gone rogue.
However, the brain has a unique protective barrier that blocks most immune cells, as well as chemotherapies.
Radiation is good at penetrating that barrier, but it can damage the DNA of healthy as well as malignant cells.
In contrast, Optune's low-intensity electric fields not only penetrate the barrier, but selectively disrupt the division, or mitosis, of cancer cells, setting them up to die by a process called apoptosis. Because healthy brain cells generally aren't dividing, they remain unharmed.
Novocure scientists demonstrated this in cells in lab dishes, and in animals. But the first big study in humans was equivocal. The electrified head dressing was no better in terms of survival than chemotherapy. Then again, it was no worse. And patients in that initial study had recurrent glioblastoma - the toughest of the tough to treat. In a controversial 2011 decision, the FDA approved Optune for such advanced patients.
The latest study enrolled about 700 newly diagnosed patients who had finished standard treatment.
In addition to better overall survival, the Optune group went longer without tumor progression - a median of seven months versus four months for Temodar alone. Scalp irritation, the most common side effect of the device, was easily managed with hydrocortisone cream.
"It's far from being a cure, but it's another step in the right direction," said University of Zurich oncologist Roger Stupp, who led the new study. "We have demonstrated the proof of principal . . . that such a device and approach is a valid anticancer therapy."
Novocure, with offices in the Channel Islands, Switzerland, Japan, Israel, and Portsmouth, N.H., has begun testing tumor-treating fields in lung, pancreatic, ovarian, and other cancers.
Nonetheless, Duke University neurosurgeon John H. Sampson was reserved in a JAMA editorial accompanying the glioblastoma study. He said the electrical fields were "purported" to disrupt mitosis, and "the mechanisms whereby this novel approach can treat tumors and leverage chemotherapy remain unclear."
Doubts are understandable, said Steven Toms, a neurosurgeon at Geisinger Health System in Danville, Pa., where Coleman and 23 patients were enrolled in the study.
"When I first heard of this therapy, I was rather disparaging," Toms recalled. "I believe I said something like, 'Putting tin foil on your head and getting beams from Mars should be as effective.'
"But by the time I treated my third patient, I realized the device seemed to be having an effect," said Toms, who has been a paid adviser to Novocure. "It didn't surprise me that the results came out the way they did. But it's been a bit of a hard sell to our colleagues in oncology."
A hard sell to Medicare, too. Most private insurers cover Optune, but the Centers for Medicare and Medicaid Services has deemed the $21,000-a-month device "medically unnecessary." Novocure hopes that will change as a result of the new FDA approval.
About 260 centers worldwide now offer Optune. Prescribing physicians must be trained to adjust placement of the transducers based on MRI brain scans every few months. Patients are taught to change the transducer arrays once or twice a week.
Coleman, in Lock Haven, continues to get coverage of Optune through the study.
His first symptom of brain cancer was on Halloween in 2011, while he was home with his toddler daughter. He recalls a blinding headache, vomiting, and frantically calling his wife, Amanda, at her job.
When he regained consciousness a month later - after surgery to remove the bleeding tumor and a coma induced to allow healing - he was given a grim prognosis. He was also offered the chance to try something that sounded like science fiction.
"I was like, 'Heck, yes. I'll try anything. I have a 3-year-old daughter,' " he said.
That daughter, now 7, calls the white bandages that anchor his transducers his "snow hat." He and his wife have added a son, now 21 months old.
Coleman discontinued Temodar about six months ago but still wears Optune almost round-the-clock. He gets moral support from an online group of kindred survivors at Geisinger.
"At first, I wasn't confident enough to put the electrodes on - now I do that myself," he said. "Some women put a wig over it, but I'm a hot-bodied person and if it gets too hot, it will start erroring. Sometimes I put a bandana over it."
"At first, it was inconvenient," he admitted. "But like I say, it beats the alternative. I praise the surgeons at Geisinger, and Novocure. It keeps me chugging along."