Last month, Duke surgeons successfully removed a tumor from the nasal passage of a five-year-old, marking the first use of a remote-controlled radiation device in a pediatric case.
"What made this operation so successful is that it took a lot of work from a team of people," said Dr. Greg Hulka, chief of pediatric otolaryngology and assistant professor of surgery. "[The procedure is] complicated... and yet, everything worked out perfectly in the end."
During tumor removal operations, microscopic pieces often remain even after the bulk of the tumor has been excised. In order to eliminate these tiny pieces without harming internal organs or tissues, Duke surgeons use a technique known as intraoperative radiotherapy.
"This method of radiation provides two advantages [over external radiation]," said surgeon Dr. Edward Halperin, L.R. Prosnitz professor and chair of the department of radiation oncology. "It provides the [surgeon with the] ability to identify a specific, localized area for radiation and the ability to avoid complications caused by external radiation by moving normal tissue out of the way."
In this procedure, a large box connected to a computer console delivers high doses of radiation via plastic catheters to a localized area in the patient's body. A small piece of iridium--no larger than a grain of rice--serves as the radiation source. Duke surgeons have used intraoperative radiation on 10 individuals over the past year.
"In certain situations, it's very difficult for a surgeon to get an adequate margin of area around a tumor [site], so this device provides a neat way for surgeons to improve the ability to give more radiation safely," said Dr. Christopher Willet, a radiation oncologist at Massachusetts General Hospital in Boston. "This type of therapy is another tool to facilitate and improve outcomes of treatments that have been combined with other forms of radiation and surgery."
After radiation, the patient is taken back to an adjacent operating room to complete the surgery. However, because patients are exposed to radiation and require additional operative time under anesthesia, surgeons have taken several safety precautions. "During the procedure, we use special monitoring devices and television cameras to watch the patient's progress," Halperin said. "We can also control the robot remotely to stop if there are problems."
The treatment is used primarily for those with advanced carcinoma of the rectum or sarcoma of the back of the abdomen, and it may broaden available therapies for a select group of patients in the future. "A surgeon might be willing to take on cases of larger adherent carcinomas that they normally wouldn't tackle," Halperin said.
However, since the technique can be used to treat a limited number of cancers, physicians estimate they will use the device once or twice a month. Researchers are interested in conducting other tests with the device to maximize its usage.
Duke is one of seven institutions that provides intraoperative radiation in the United States; Massachusetts General is another. "There has been rising interest in this type of radiation here because a surgeon can control and direct radiation to areas that are of most concern and not have to radiate surrounding tissues," Willet said.
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