CyberKnife Brings Powerful Weapon to Middle TennesseeFirst do no harm.
This guiding precept impacts every decision a physician makes. For radiation oncologists, it has sometimes been a major stumbling block when it comes to fighting aggressive or hard-to-reach tumors. After all, the life-saving radiation therapy also carries with it a huge risk to the healthy tissue surrounding a lesion.
After researching available options, the Sarah Cannon Cancer Center has opted to purchase a knife that will never make a cut, yet promises to be a highly effective weapon in the war on cancerous and benign tumors. Rocky Billups, RN, MS, administrator for SCCC, said installation of Middle Tennessee's first CyberKnife System® begins later this month at Centennial Medical Center. He anticipates the robotic radiation system will be operational by July.
Although TriStar considered purchasing a Gamma Knife, which is widely recognized as an effective radiosurgical treatment option, the hospital system ultimately preferred the versatility and advanced technology of the newer CyberKnife, according to Billups. He noted the device by AccuRay received FDA approval in 1999 for intracranial use and in 2001 for extracranial radiosurgery allowing for whole body treatment.
D. Edward Hunt, MD, a radiation oncologist at Centennial added the CyberKnife is really the next iteration in targeted, shaped beam therapy.
"The Gamma Knife has been around for a number of years, but it still only treats intracranial lesions," explained Hunt. "The CyberKnife has equal efficacy but also treats other lesions within the body such as lungs, spine, prostate and liver."
Hunt added the newer technology is ideal for treating both cancerous and benign tumors that are medically inoperable or surgically complex. It also gives patients who might be candidates for surgery an option that is less invasive, highly accurate and requires no significant recovery time.
What sets the technology apart, Hunt said, is the way the radiation is being delivered. In an ideal setting, a radiation oncologist uses three-dimensional imaging technology to create an advance treatment plan. On the actual day of the appointment, a linear accelerator delivers the dose based precisely on those plans.
"We assume that once that treatment has started, everything is static," noted Hunt. "In the real world, people fidget and move and cough. It's hard to get people to hold their breath for ten minutes," he added wryly.
Unfortunately, any tiny movement puts normal structures adjacent to the tumor in harm's way. Hunt pointed out side effects come from toxicity to the adjacent, healthy tissue … not the diseased tissue targeted by the accelerator.
Billups said the Gamma Knife requires rigid fixation to stay on target with the prescribed treatment plan. A halo, which is screwed into the bone of the skull in four places, is utilized to help a patient achieve maximum stillness.
With the CyberKnife, concerns over movement … along with the need for a halo … are eliminated. "It actually does real time imaging during the treatment," Hunt said.
He explained physicians use implanted radiopaque marker beads to track the movement of a tumor throughout the respiratory cycle with the angle and aim of the radiation beam automatically shifting as the patient breathes. For spinal lesions, the robot is intuitive enough to follow even fractional movement in the bony anatomy.
With that high degree of control, Hunt noted, physicians have the ability to "minimize side effects associated with treatment. It allows us to deliver a high dose of radiation in a short time … sometimes as few as one fraction, but usually one-to-five fractions depending on the region of the body."
The hope is that the speed will ultimately result in improved quality of life, patient convenience and a cost savings. Hunt pointed out traditional external beam radiation treatment for prostate cancer would typically consist of a 15-minute session Monday-Friday over eight weeks. With the CyberKnife, the protocol calls for a 45-minute session over a five-day period … one week instead of eight.
"Hopefully, we'll accomplish the same results in a shorter period of time," he said. "A lot of the outcomes data is under investigation at this point. We're certainly hopeful we're going to see better outcomes over time with greater efficacy."
Hunt added, it's already recognized that patients enjoy a better treatment experience "because we're able to highly conform this beam with a high dose of radiation in close proximity to other areas and to minimize … to the limit of current technology … damage to normal structures."
Billups said one testament to CyberKnife's efficacy is the increase in interest by facilities to adopt the technology. The Centennial Medical Center system is Tennessee's third (the other two are in Bristol and Knoxville), but Billups noted that Memphis received CON approval this past summer and there is a pending CON request to add the equipment in Chattanooga.
Billups added Sarah Cannon Cancer Center is eager to work with all area physicians with patients who might be candidates for CyberKnife radiosurgery.
"We want to make sure the communication is as fluid as possible," he said.
To that end, Billups is in the process of hiring a nurse navigator who will schedule patients, verify insurance coverage, handle patient education, and act as a liaison between the patient, referring physician and radiation oncologist at Centennial Medical Center. When CyberKnife goes live this summer, Hunt and James R. Gray, both with Tennessee Oncology, will be the two radiation oncologists initially trained in the technology. However, Hunt added, "We hope to be busy enough to need more staff."