Gregory Gagnon, MD, clearly remembers March 2002. That was the month when he and his colleagues in radiation medicine began treating patients with the CyberKnife. Soon, he will have another date in his memory: when the second CyberKnife at Georgetown University Hospital becomes operational.
The CyberKnife system uses military technology similar to that used for cruise missile guidance to deliver concentrated and accurate beams of radiation to a targeted tumor or lesion. One of the latest advances in radiation oncology, the CyberKnife is able to create 1200 to 1400 beams that are capable of targeting the tumor with pinpoint accuracy. This three dimensional approach to deliver a focused radiation does achieves an outcome similar to surgery with many fewer side effects.
Georgetown University Hospital was the sixth center in the United States to begin using the CyberKnife for cancerous and non-cancerous tumors in the head, neck, and spine in March 2002. The Hospital continues to provide the only CyberKnife services in the District of Columbia and, since that time, physicians have treated around 1500 patients.
Dr. Gagnon is Chief of Radiation Medicine at Georgetown University Hospital explains why this new technology is so important. “For advanced cases, surgery on the head and neck are very difficult and only 70 percent of surgeries are successful. Even when they are, the side effects can be great. With CyberKnife, our success rate on those surgeries is 95 to 100 percent.”
The decision to purchase and install a second machine was not made lightly with its $6 million price tag. But over the past several years, the CyberKnife has been operating 12 hours a day, nearly everyday, in order to accommodate the many patients for whom it is the best, and in some cases the only, treatment option.
Lombardi’s Interim Director Anatoly Dritschilo, MD, is an attending radiation oncologist at Georgetown University Hospital. “With the CyberKife, we are able to provide an alternative to surgery that has little to no side effects,” he said. “The most common side effect reported is a little fatigue, but patients are able drive themselves home after their hour-long treatment.”
Before receiving the actual CyberKnife radiation treatment, patients are first fitted with tiny gold markers that direct the CyberKnife's radiation beams to the tumor with pinpoint accuracy. Three to four of these tiny gold chips, about the size of a chocolate sprinkle are inserted into or near the tumor. Traditionally those are inserted through a needle using CAT scan guidance or surgery.
However, new techniques pioneered at Georgetown University Hospital involve no surgery and pose fewer risks like infection or bleeding. For lung cancers, pulmonologists are inserting the gold chip by placing it on the end of a video flexible bronchoscope, which is directed through the airways to the tumor. Similarly, for GI cancers, gastroenterologists are able to implant the chips using an endoscopic ultrasound, a method that has an extremely low complication rate.
So far physicians have used these new methods for "inoperable" cancers of the lungs and those that are located anywhere along the GI tract including the esophagus, behind the heart, pancreas, liver and all the way down to the duodenum. The technique can also be used for rectal tumors.
“In the area we treat with the CyberKnife, we are really able to get rid of the tumor. And this is different from standard radiation therapy which kills a little bit day by day. Here, we are specifically eliminating the whole tumor in one go,” said Dr. Gagnon.
Currently, patients who receive treatment with the CyberKnife are those with the fewest options for alternative treatment: patients with medically inoperable tumors or with cancers that have failed conventional radiation therapy. By introducing a second machine, Dr. Gagnon and his colleagues hope that they will be able to develop protocols for patients at earlier stages of their disease.
“We see the role of CyberKnife radio surgery as an additional treatment along with other therapies like surgery and chemotherapy,” said Dr. Gagnon. “CyberKnife can destroy the tumor without the need for surgery and in some cases patients can continue their chemotherapy at the same time. With those two weapons together we hope to improve patients' chances of survival and improve their quality of life."