By Jeremy Olson

Minneapolis Star Tribune

ROCHESTER — Until this week, Mayo Clinic had tested its $180 million proton beam accelerator only on water, a cadaver and cuts of meat donated by Ye Olde Butcher Shoppe in Rochester.

But Monday, with a turn of a safety key and a press of a “beam on” button, radiation therapist Rebecca Keller sent positively charged protons through a series of powerful magnets, accelerating them to 60 percent of the speed of light, and focused them straight at the bottle cap-sized tumor in the brain of Ashley Sullivan.

Physicists and cancer specialists crowded over Keller’s computer in the control room of Mayo’s new proton beam center to watch protons pepper the tumor. “That’s it,” said Michael Herman, the center’s chief physicist, once the tumor was coated.

So began one of the most ambitious, costly bets in Mayo’s history — an investment in an emerging radiation therapy that Rochester doctors believe will revolutionize cancer care, but which critics believe is wasteful technology that will accelerate the high and rising cost of medicine in the United States.

The proton beam has been promoted as a more precise form of cancer treatment than conventional radiation: Because it can halt the cancer-killing particles at the site of a tumor, it is less likely to expose healthy tissue to harmful radiation.

But proton therapy can cost six times more, and there is insufficient research to determine which types of cancer it treats more effectively. Some insurers are reluctant to pay the bills, while economists have questioned its purpose.

“It is the Death Star of medical technologies,” said Amitabh Chandra, a health economist at Harvard University. “Nothing so big and useless has ever been developed before.”

In Ashley Sullivan, however, Mayo cancer specialists have found just the right first patient. Research supports its use for certain adult brain tumors and tumors in children, whose longer life spans increase their risk of second cancers and complications from radiation exposure.

Sullivan, 29, discovered her tumor when she had blurred vision while driving last fall. An imaging scan showed it pressing her optic nerve. Surgery in January removed some of the tumor, but doctors recommended proton therapy to target the rest because it would reduce radiation exposure to her brain and the chance of memory or cognitive side effects emerging years later.

“Her tumor is … 85 to 95 percent curable with radiation,” said Dr. Nadia Laack, a Mayo radiation oncologist. “These patients have a long life ahead of them. They are the ones at risk for side effects from our cancer treatments.”

Trouble is, brain tumors like Sullivan’s aren’t common, so treating them alone won’t pay the huge costs for most proton centers. Researchers have found that cities big enough to support a single pro sports team can support a single proton beam center, said Dr. Peter Johnstone, who directed the proton beam facility at Indiana University until it closed due to financial and competitive pressures.

Some cities have too many proton beam centers, leaving them to fight for patients and to push pricey proton therapy, even in cases where its superiority hasn’t been proven, so they can pay off their loans and investors, said Johnstone, who has published several studies on the economics of proton beam therapy. “If you’re using venture capital money with a desire for a rapid return on investment, it’s not going to be very sustainable.”

Which is why Mayo’s approach is intriguing. Instead of venture capital, Mayo used fundraising and a $100 million gift from Iowa philanthropist Richard Jacobson. To advance research on the benefits, Mayo plans to subsidize the portion that exceeds the cost of standard radiation.

Resistance to proton therapy is similar to the resistance that occurred decades ago when radiation with the first linear accelerators emerged as an alternative to now-outdated cobalt treatments, said Dr. Sameer Keole, medical director of proton beam therapy at Mayo’s Arizona campus, which will offer the technology next year.

“We have these [arguments] over and over throughout the course of time,” he said. “Mayo isn’t looking at it from a 5- or 10-year viewpoint. Mayo is looking at it as, ‘What’s the future of radiation oncology?’ “

Sullivan’s interest is more immediate. The discovery of a brain tumor was just the latest medical hardship for the Korean adoptee; she was diagnosed as a child with a rare condition, Sjögren’s syndrome, which left her with rheumatoid arthritis.