CyberKnife still ‘the gold standard’ for stereotactic body radiosurgery treatment
David Bryant, MD
In the fall of 2005, Via Christi Health opened a 4,000-square-foot CyberKnife Center in Wichita, an investment made to ensure that regional cancer patients had a full complement of high-tech, close-to-home treatment options.
The CyberKnife Robotic Radiosurgery System was already being used with great success elsewhere around the country to provide a ray of hope for patients with cancerous tumors or lesions considered untreatable or inoperable because they were in hard-to-reach places or because the patient had other medical conditions that prevented surgery from being an option.
But patients living in and around Wichita had to travel to centers that were hours away to benefit from this technological marvel, which can painlessly destroy tumors anywhere in the body where treatment is indicated, without damaging healthy tissue.
“In terms of accuracy and precision for moving targets, it’s hard to beat CyberKnife.”
— Via Christi radiation oncologist David Bryant, MD
Today, nearly 2,600 patients have been treated at the Via Christi CyberKnife Center, benefiting from the expertise and skills of Via Christi’s two dedicated, board-certified radiation oncologists and a growing number of surgeons who’ve undergone training to offer this nonsurgical treatment option.
At the time the center opened on the campus of Via Christi Hospital St. Francis, CyberKnife was still in its early years. It had received FDA clearance to treat tumors anywhere in the body in 2001, just two years after it had been cleared to treat cancer in the head, neck and upper spine. Its inventor, John Adler, MD, a Stanford University physician and neurosurgeon, had studied with Lars Leksell, MD, a pioneer of stereotactic radiosurgery.
Currently, there are more than 240 CyberKnife treatment centers worldwide, with about 150 in the United States. Via Christi’s center, which has undergone numerous upgrades over the past decade, is one of two in Kansas.
Brett Grizzell, MD, a cardiothoracic surgeon at Wichita Surgical Specialists, says having close-to-home stereotactic body radiosurgery, or SBRT options such as CyberKnife, is important to the area’s quality of care.
“SBRT is an excellent complement to a comprehensive cancer treatment program when offered as part of a multidisciplinary approach to the right patient at the right time,” Dr. Grizzell says.
“… Amazingly precise”
The CyberKnife system, designed to home in on lethal cancers that have invaded the body, looks like something out of a Star Wars movie.
“In terms of accuracy and precision for moving targets, it’s hard to beat CyberKnife, as compared to other stereotactic radiosurgery options,” says David Bryant, MD, Medical Director of Radiation Oncology at Via Christi.
Unlike other SBRT systems that use a modified linear accelerator, CyberKnife is the only one with a linear accelerator, or LINAC, specifically designed for stereotactic radiotherapy. Its LINAC is mounted on a robotic arm, allowing more flexibility and freedom of movement in delivering beams of high-energy radiation.
CyberKnife’s real-time auto-correcting capability — i.e., its ability to continue to track and treat tumors as they move with a patient’s breathing or physical changes such as the bladder filling up — is another unique feature. It is the only stereotactic radiosurgery system that doesn’t use respiratory gating, in which the machine has to go on and off when movement is detected during treatment.
“It’s like having the precision and accuracy of programmed-cruise-missile technology in which all the information about the landscape and the target is inputted,” Dr. Bryant says. “But in this case, the target is a cancerous tumor and the weapon is an amazingly precise beam of radiation.”
When battling a cancerous tumor or unhealthy tissue, a small cadre of well-trained medical professionals, including a radiation oncologist, a surgeon and a medical physicist therapist, work together, using CT scans and the CyberKnife’s highly sophisticated computer program to set the coordinates and take out the target with little to no collateral damage.
“The computer figures out the best route to come in and hit the tumor, while avoiding other structures you’ve outlined that you want it to miss,” Dr. Bryant says.
While patients lie still on a bed — gazing up at a recessed ceiling panel decorated with leafy green branches interrupting a serene, blue sky — CyberKnife’s computer-guided robotic arm moves around them, aiming at tumors with pinpoints of radiation from dozens of angles. The beams are accurate to less than 1 millimeter, or about 1/25 of an inch, so nearby healthy tissue isn’t damaged.
The treatments are painless because they require no incisions or sedation, and they are done on an outpatient basis, usually in one to five consecutive sessions. Patients can go home, or even back to work, without needing recovery time.
Dr. Bryant joined Via Christi in 2008, a year after the center’s other board-certified radiation oncologist, Jon C. Anders, MD, and they share CyberKnife treatment responsibilities. Combined, they have more than 20 years’ experience in using CyberKnife.
That benefits patients, Dr. Bryant says, because “just as with surgeons, the more cases you do with CyberKnife, the better you get and the better your outcomes.”
Drs. Bryant and Anders work closely with surgeons who’ve undergone training with Accuray, the manufacturer of CyberKnife, at Via Christi. That number continues to grow, as four more area surgeons recently trained on the system.
Every week, five or more new patients are referred to Via Christi’s CyberKnife Center for a consultation. In a small consulting room, they hear about the treatment option, with a tabletop-scaled model of the system within sight, and they watch a video that demonstrates how the cancers with which they’ve been diagnosed are treated by the system.
Patients are also screened for participation in any clinical trial offered through the National Cancer Institute’s Community Oncology Research Program, or NCORP, based at Via Christi Hospital St. Francis, says Dr. Bryant, who is a participating oncologist in NCORP. At any given time, Via Christi’s CyberKnife Center is typically participating in at least one national study.
One such study in which the center will participate is looking at the treatment of oligometastatic cancers, when cancer cells from the primary tumor travel to form a small number of metastatic tumors in one or two other parts of the body. The study will look at outcomes in treating all of the tumors aggressively.