Home

Cover Story

Table of Contents

E-Newsletter

Article Archive

Editorial Calendar

Datebook

Writers' Guidelines

Orgs/Links

Opinion Polls

Reprints

Forum

For other articles and previous issues click here.

May 30, 2005

Expanding Treatment Options & Cancer Practices
By Beth W. Orenstein
Radiology Today
Vol. 6 No. 11 P. 10

CyberKnife’s approval for stereotactic radiosurgery for tumors throughout the body offers a new treatment options for cancer patients.

St. Joseph’s Hospital in St. Paul, Minn., has become a referral center for cancer patients who have tumors deemed inoperable or have previously received the maximum level of radiation. It has treated patients who come from outside the United States, from across town, and even from across the river, including from the world-renowned Mayo Clinic in Rochester.

“It’s been neat to be a regional referral center so close to the Mayo Clinic, which is just 70 miles away from us,” says Chris Laird, MHA, associate administrator of St. Joseph’s Hospital’s Center for Stereotactic Surgery.

St. Joseph’s has become a referral center largely because, since November 2003, it has had a CyberKnife Stereotactic Radiosurgery (SRS) System developed and marketed by Accuray of Sunnyvale, Calif. Developed at Stanford University in California, the CyberKnife delivers multiple beams of precisely directed radiation that converge on the tumor while minimizing injury to surrounding healthy tissue. The CyberKnife has FDA clearance in the United States and CE approval in Europe to treat tumors anywhere in the body where radiation treatment is indicated.

The broad approval differentiates CyberKnife from Elekta’s Gamma Knife, which is currently approved for only head and neck tumors. The Gamma Knife is the original SRS system and has a 30-year track record. CyberKnife was first developed for the treatment of brain tumors. It received FDA clearance in 2001.

St. Joseph’s is one of roughly 100 hospitals and medical centers worldwide that have either installed or contracted to purchase the CyberKnife. The system has been used to treat more than 12,000 patients to date, says Eric Lindquist, MS, MBA, senior vice president and chief marketing officer of Accuray.

Extracranial Tumors
Centers that have a CyberKnife report using it successfully to treat tumors not only of the head and neck but also of the spine, lung, pancreas, liver, colon, prostate, breast, and eye. The tumors can be primary or metastatic cancers. Some centers have also had very good results with using it to treat vascular abnormalities such as arteriovenous malformations and functional problems such as trigeminal neuralgia.

The Alvin & Lois Lapidus Cancer Institute at Sinai Hospital in Baltimore has had a CyberKnife for two years. The first six months it was used exclusively for tumors of the central nervous system, says Linda Rogers, RN, MBA, CPA, director of cancer services. “We needed to feel comfortable with it,” she says.

Now it is used for broad applications, Rogers says. “We have treated a lot of pancreatic lesions as well as a lot of lung lesions that would otherwise be inoperable… One of our ophthalmologists has treated orbital tumors,” she says.

“We haven’t done primary prostate treatments, but we have done some prostate boosts,” says John “Denny” DeLange, RT(T), BS, director of radiation oncology for the Miriam R. Hart Regional Radiation Center/Rocky Mountain CyberKnife Center at Boulder Community Hospital in Colorado. “We’ve also done pancreas, liver, kidney, and lung, as well as intracranial and spine lesions.”

Less Invasive
At St. Joseph’s, Laird says, “we truly believe that the CyberKnife is a game-changer.” Some intracranial tumors, such as acoustic neuromas, are an obvious example, he says. Previously, they required a craniotomy—open surgery that involved a four- to eight-hour procedure, including opening the cranium, as long as a nine-day hospital stay, and up to a six- to nine-week recovery and rehabilitation period. Sometimes even a craniotomy was not an option because the tumor was deep in the skull or too close to or wrapped around other critical structures.

Now tumors can be ablated with three 45-minute treatments as an outpatient, Laird says. “Patients walk in, sit on the table, get treated, and walk out. They come in [the] next day and the next day and do the same thing and they are done. The improvement in their quality of life is just amazing.”

Where appropriate, St. Joseph’s neurosurgeons are also using the SRS to boost open surgery as well, Laird says. The surgeons will perform open surgery to remove 90% of the tumor in the brain and use the CyberKnife to remove the last 10%, which is where the risk lies. “Instead of going in and cutting, they will use the CyberKnife to finish because it has sub-millimeter accuracy,” he says.

Building Practices
Lindquist says hospitals and centers that have a CyberKnife are finding that it attracts new patients and increases their practice volumes. It’s an advance that excites and opens up radiation oncology practices, he says.

“We have done a fair bit of analysis here and we have found that the radiation therapy practice market has remained relatively flat,” Lindquist says. “The introduction of new technology such as intensity modulated radiation therapy [IMRT] and things of that nature have really helped radiation oncologists deliver better treatments to their existing patients, but it hasn’t brought them new patients.”

The CyberKnife, he says, gives centers access to a whole group of patients they might not otherwise have seen. “You don’t put in a CyberKnife and cannibalize your existing patients. It opens up new referral patterns into the department of radiation oncology.”

Rogers, of Sinai Hospital, says its radiation oncology practice has grown tremendously in the last three years and the CyberKnife is a contributing factor.

“The CyberKnife is one variable,” she says. “You have to have the right people. You have to have good care. And you have to have the right technology. Having a CyberKnife helps to serve the technology component that you need.”

DeLange, of Boulder Community Hospital, one of the first community hospitals to have a CyberKnife, has also found that the system has added to its patient volumes. “There’s a whole different segment of the population that can benefit from the CyberKnife,” he says. “It really doesn’t take away from the radiotherapy business. We’ve basically added a lot of patients to our clinic based on the CyberKnife. We wouldn’t have seen them otherwise.”

The additional patients include those who have received maximum doses of radiation and those whose tumors are otherwise in inoperable locations.

The list price of a CyberKnife is $3.7 million and it can be installed in conventional linac bunkers, which house linear accelerators, treatment cells, or concrete-shielded rooms, Lindquist says.

Specialist Team
The key to a successful SRS practice is to have a team of specialists to treat patients because the process involves surgery as well as radiotherapy, Lindquist says. Centers need surgeons, radiation oncologists, and physicists. St. Joseph’s CyberKnife team consists of two radiation oncologists, three neurosurgeons, a general surgeon, and a pulmonologist. The pulmonologist is a recent addition and is helping to attract patients with lumps and masses in their chests, Laird says.

Practitioners don’t see the CyberKnife replacing the Gamma Knife. The Gamma Knife is “wonderful technology. It has done great things and continues to do great things,” DeLange says.

But the CyberKnife has several advantages, including the fact that it is frameless. For brain tumors, the patient’s head does not have to be bolted to a frame with skull pins to keep it still, which is how the Gamma Knife system is designed. The CyberKnife uses skull or bony landmarks to target treatments. In many extracranial cases, fiducial markers are implanted in the soft tissue before the procedure begins. The markers help the system track the tumor if the patient moves.

Targeting System
The CyberKnife uses real-time x-rays to establish the position of the lesion during treatment and then dynamically brings the radiation beam into alignment with the observed position of the treatment target. Each beam is aimed independently, without a fixed isocenter. If the patient moves, the computer detects the change and corrects the beam pointing in near real time.

Most patients experience few, if any, side effects. Some suffer headaches and extreme fatigue after having SRS treatment, and a small number lose their hair.

Treatments can cost between $25,000 and $60,000. Patients can require anywhere from one to five fractions. Conventional radiotherapy typically requires 30 to 40 sessions.

Traditional radiation therapy tends to negatively impact surrounding tissue and organs whereas the CyberKnife can pinpoint the radiation and deliver the highest possible safe dose in fewer visits.

Treatments are performed on an outpatient basis and typically last between 30 and 90 minutes, depending on the tumor’s size and location. Patients lie on the procedure table as the CyberKnife hovers above them—its robotic arm moving without touching them to treat all areas of the tumor. No anesthesia is required, although some patients may need mild sedation.

Usually, once patients undergo their first fraction and see how it is done, they are fine, DeLange says.

While still considered somewhat new to the market, most insurers will cover the cost, the centers using CyberKnife have found.

“We have had only two patients that insurance would not pay for,” Laird says, “and we decided to move forward and treat the patients anyway. Insurers are not familiar with CyberKnife applications and we continue to educate and have our medical directors get on the phone with the payors. We’ve had very receptive payors in the Twin Cities community for CyberKnife treatment.”

Reimbursement
DeLange says insurers seem open to SRS treatments, perhaps because it is much less costly in the long run when compared with open surgery and hospital stays. “Economically, it makes sense,” he says. Also, for some patients, it is their only option because their tumors are inoperable.

Boulder Community Hospital averages roughly three patients per day with its CyberKnife. “We could treat as many as five or six,” DeLange says, “but we would be running a full schedule.”

St. Joseph’s goal is to treat five patients per day in an eight-hour time block. The issue is more scheduling and support than anything else, Laird says. “What I’ve heard from radiation oncologists and physics staff is that a CyberKnife patient is about three times more intensive than a typical external beam or IMRT patient. That’s where the logjam occurs if you don’t have the right staffing support.”

In 2002, Accuray introduced its Synchrony system for tracking tumors in or near the lungs as they move. Synchrony records the breathing movements of a patient’s chest and combines that information with sequential x-ray pictures of fiducial markers inserted inside the tumor to enable precise delivery of radiation during any point in the respiration cycle.

Tumor tracking not only makes the procedure much easier than the breath-hold technique previously used, but it also reduces the time it takes to get the patient on and off the table, DeLange says.

Referral Base
One of the biggest challenges of developing an SRS practice, the administrators agree, is developing a referral base.

“One of the most important things that a clinic needs to do is to make sure you have a strong base of referring physicians, mostly surgeons and radiation and medical oncologists,” DeLange says. “It’s important to have them understand what the CyberKnife is and what it can do now—and may be able to do in the future.”

Users believe they have only just begun to tap the system’s applications. “I think this will continue to expand,” Laird says. “There is no doubt in my mind. We’re interested in getting thoracic, urology, and colorectal surgeons involved in our program just as another option for patients.”

While CyberKnife does not have as long a history of data as the Gamma Knife, Rogers is confident that the body of literature supporting its different applications will only grow. DeLange agrees. “I think as time goes on, there will be more applications for CyberKnife,” he says. “We’re really trying to build a good database of the things we know that the CyberKnife was really developed for—intracranial and spine—but knowing that extracranial lesions in the body are something we can work on.”

DeLange noted that it took the Gamma Knife many years to gather the data it has. “So we’re putting together good studies and good abstracts on different places of the body and different tumors that the CyberKnife can be used to treat successfully,” he adds.

The CyberKnife Society and Users Group, which includes many leading surgeons, oncologists, and medical physicists, is helping to track and develop applications. Its fourth annual meeting, held last month in Half Moon Bay, Calif., attracted more than 200 experts for scientific discussion and professional development. The four-day symposium was sold out weeks in advance. Particularly well-received at the conference, Lindquist says, were rigorous scientific sessions on new advancements in urology, thoracic procedures, and general surgery.

— Beth W. Orenstein is freelance writer based in Northampton, Pa. She is a regular contributor to Radiology Today.

Subscribe to Radiology Today Magazine!