Cyber Rays of Hope

State-of-the-art digital systems are allowing doctors to treat patients’ insides from the outside
Cyberknife Machine
CyberKnife Photo by Roy Ritchie

In a narrow, dark room at Saint Joseph Mercy Hospital in Ann Arbor, a 23-inch computer screen beams an image of a human pancreas in the kind of vivid color and accompanying graphs, numbers, and control metrics that would impress any 14-year-old PlayStation addict.

The organ itself is gray, the nearby kidney is green and the tumor is bright red, encircled by light blue lines. This, says Sylvia Davidson, radiation therapist in the oncology radiation department, is a CT scan that will become a “digitally reconstructed radiograph,” or a DRR. Translating, she adds, “They take the CT and make it look like an X-ray.” A very pretty X-ray.

The sophisticated computer software the screen represents controls the 12-foot high, 3,000-pound, $4-million piece of robotic equipment in the room a few feet away. There, a dummy’s head, dubbed “Bob” by the staff here, serves as a quality-control device. Daily testing ensures that the beams of tumor-burning radiation the machine silently emits are delivered with the promised “sub-millimeter” accuracy. A complicated tracking system enables the machine to adjust immediately to any patient or tumor movements.

This is CyberKnife. It is, say those who have invented, manufactured, purchased or used the machine, the most effective weapon in the non-invasive fight against tumors, especially malignant ones. Among such “stereotactic radiosurgery” devices, as they are called, CyberKnife makers trumpet its revolutionary ability to treat tumors outside the skull, offering new hope to patients.

It also offers, not incidentally, a good example of new millennium medical marketing, which hopes to hit with sub-millimeter accuracy its target audience. An aggressive campaign to advertise Michigan’s only CyberKnife includes 32 highway billboards along with direct-mail fliers, mall and radio advertising, Web sites and other tentacles of precision marketing. The bill for all of this was about $465,000.

So, is CyberKnife worth all this money and brouhaha? And is it really the advancement over other such treatment devices it claims to be?

That probably depends on the patient, the disease, the particular device, and the doctor. Competitors such as Gamma Knife (Detroit Medical Center/Harper University Hospital; William Beaumont Hospital; Barbara Ann Karmanos Cancer Institute), which has been around several decades; Novalis Shaped-Beam Radiosurgery, or BrainLAB (Henry Ford Hospital); and the TomoTherapy HI-ART System (Barbara Ann Karmanos Cancer Institute), all deliver radiation to tumors. The non-invasive technology offers certain benefits, such as pain-free, anesthesia-free treatment. And it also allows for at least some treatment of tumors that otherwise are inoperable. Complications from, for instance, longer hospital stays that are not required with such treatment, are reduced as well.

CyberKnife, St. Joseph’s points out, is treating large numbers of tumors outside the brain, a key reason the hospital chose the system. Donna Ingleby-Buhr, 80, of Canton was one patient who benefited from this capacity. After having surgery for endrometiral cancer in February at St. Joseph’s, her doctors found a nodule on her lung. It was determined to be cancer, but a different cancer — so her original cancer had not metastasized.

“I was scheduled for chemo,” Ingleby-Buhr says, “but the chemo wasn’t going to do it. They decided the only thing that could help me was CyberKnife.” She was treated in July. “You can’t feel a thing,” she says. “I kept lying there, waiting for something to happen.”

The other differences between systems are really more in how each system delivers treatment. For instance, Gamma Knife uses a head frame that must be fastened to a patient’s skull. CyberKnife uses a soft, malleable plastic face mesh, which allows flexibility in treatment, says Dr. Walter Sahijdak, a radiation oncologist and one of two St. Joseph physicians pictured on those billboard ads and fliers.

“We’ll decide on what we think is a safe treatment in terms of dose. We can break down treatment; we can do more than one. That’s an advantage. So for patients with tumors near critical structures” such as eyes, major organs, the brain stem, “we’re able to deliver doses over more than one session because we don’t have to bolt them in.”

Ingleby-Buhr found that aspect of her treatment especially attractive. “I had four treatments, all in one week,” she says. But, unlike other systems that stretch multiple treatments over a month, for example, “this is over and done with.”

Dr. Geoffrey Thomas, a neurosurgeon and the other billboard doctor, says the CyberKnife’s precision is its most important asset. Doctors, with the help of senior medical physicist Matthew McMullen, develop a treatment plan and program it into the computer, an intensive, highly detailed task. “We tell the computer what to do. The robot goes by computer to various stations” in the body determined by the prior program. “And we picked these stations out so the radiation beams are missing or minimizing doses to critical structures.”

CyberKnife’s touted tracking system works in two ways. One is via the spine. It locates, Davidson says, 82 different points on a designated section of the spine and “uses those 82 points to match up to the images in the computer to tell us what we’re tracking and how it’s moving.”

The computer also can track via a tiny gold marker inserted into the tumor by a biopsy needle — which is what Ingleby-Buhr’s case required. Using either mode, the giant robot delivers its “little bit of radiation,” as Davidson phrases it, as it constantly corrects for movement, then delivers the next hit of radiation from a slightly different angle — one of the precision aspects of the treatment.

Competing systems have their own claims. For instance, the Karmanos Institute’s TomoTherapy system uses Intense Modulated Radiotherapy (IMRT), and is newer than CyberKnife, which dates to 1987. Karmanos’ literature calls their system “the world’s most advanced cancer treatment system” that allows the delivery of “more precise and powerful doses of radiation to a tumor while avoiding critical structures ad healthy tissue.”  Patients lie on a couch that moves through the “tomotherapy machine” first for location and three-dimensional imaging of the tumor, then to receive radiation in a “spiral pattern” from a 360-degree radius.

Karmanos doctors say the 3-D process also adjusts during treatment. They treat brain, lung, prostate, and other tumors.

Meanwhile, Gamma Knife is the “gold standard” for brain tumors, according to the Web site of Wake Forest University Baptist Medical Center in Wake Forest, N.C., which is one of Gamma Knife’s busiest users. The unit uses a “201-source cobalt unit” and a “lightweight stereotactic head frame fixed to the outer skull,“ and also has the 3-D imaging features. The site actually compares the Gamma Knife and CyberKnife, claiming superiority in accuracy and dosage, and arguing that multiple visits are a disadvantage.

Theodore Lawrence, professor and chair of the department of Radiation Oncology at the University of Michigan, said U-M has had devices similar to CyberKnife for years, and, when updating its equipment, chose Trilogy, which they believe is superior to CyberKnife. The Trilogy system, for instance, can produce a CT scan of the patient during treatment, at the moment the radiation is delivered. He claims, “CyberKnife can’t do that.”

Differences and debates aside, it’s important to remember that all of this technology offers new flexibility and hope to patients such as Ingleby-Buhr. It’s also important to remember that all technology is limited, too, stresses Thomas.

“This won’t replace all other tumor treatments,” he says. “It just won’t. There are certain things that it’s better for. There will be plenty of tumors we will treat with surgery.”

But CyberKnife, or any radiosurgery, enables doctors to customize treatment. For example, a surgeon can leave small amounts of tumor near those “critical structures,” allow a patient to recover a bit, and then remove the residual tumor via CyberKnife’s precise radiation.
Thomas and Sahijdak emphasize the central points to keep in mind with CyberKnife. Thomas says CyberKnife uses “a team concept, a new way of looking at treating diseases. You bring everybody’s expertise in to treat that disease.”

Second, CyberKnife does not necessarily “cure” inoperable brain tumors. It does not ensure long-term survival, although it certainly can extend survival. But with cancer, survival is not the only issue, Sahijdak says. “The other issue is quality of life. We’ve had a few patients go home after treatment, come back and say, ‘I’ve been sleeping in a La-Z-Boy for months. I got to sleep in my bed for the first time last night.’

“With brain lesions, we can control their brain symptoms, the things that are inhibiting patients from interacting with their families. The reason it’s called radiosurgery is because it’s able to take out the area without removing it. So it’s a way to…allow patients to not have symptoms and be at home. As cancer becomes more of a controllable disease — with the advances that are happening throughout oncology, not only with what we do ­— this offers us another way to help patients get back to living.”

That is what Ingleby-Buhr hopes for. She will learn in late September how effective the treatment was. “Hopefully, they’ll tell me I’m fine so I can go home and live a long life.”

James is a Brighton-based freelancer. E-mail: