IGRS Device Used to Control Metastatic Cancer

Doctors at Virginia Commonwealth University (VCU) Massey Cancer Center in Richmond are among the first in the world to use new image-guided radiosurgery (IGRS) technology from Varian Medical Systems to control the spread of metastatic cancer.

Theodore Chung, MD, PhD, a radiation oncologist and researcher for Massey and an associate professor at the VCU School of Medicine, used the new technique to offer new hope to a 47-year-old mother of four whose breast cancer was spreading to her brain and liver. The patient was first treated for breast cancer five years ago, and it seemed to be under control until metastatic lesions began to appear. Chung treated several of her metastatic lesions with IGRS, an ultraprecise procedure that makes it possible to monitor, track and target tumors with high doses of radiation in just one to five treatment sessions.

"Our new real-time imaging and targeting capabilities are helping us turn cancer into a controllable disease," said Chung. "These recent advances in radiosurgery are opening up an era in cancer treatment where we can actually begin to control metastatic spread."

Chung and his team deliver IGRS treatments using Varian's Trilogy linear accelerator with an Onboard Imager device for pinpointing tumors and targeting them with precisely shaped therapeutic beams. They also use an optical system to continuously monitor and ensure that the patient remains properly positioned during treatment.

To further enhance accuracy and address the problem of tumor motion during treatment, the team uses Varian's RPM respiratory gating system to synchronize beam delivery with patients' natural breathing patterns.

For the patient with metastasized breast cancer, Chung and his team were able to use their IGRS system to spare significant amounts of her healthy tissue while treating three separate brain lesions in a single course of treatment.

"One lesion was close to the motor strip," Chung said. "Too much dose to this area might have damaged her ability to move. The second lesion was close to the brain stem -- another area that had to be carefully protected during treatment. By using Trilogy's Onboard Imager to take radiographic x-rays, we were able to quickly line up bony anatomical landmarks each day and position the patient properly for her treatments."

The optical positioning system made it possible for Chung to avoid using a conventional head frame that must be screwed into a patient's skull to keep it immobilized during treatment. To deal with a metastatic tumor that appeared in the patient's liver, Chung and his team delivered a "gated" radiosurgery treatment on the Trilogy machine that compensated for respiratory motion during the sophisticated treatment. The Massey Cancer Center was one of the earliest adopters of Varian's RPM respiratory gating technology for targeting tumors that move during treatment due to the patient's breathing.

"She's doing fine right now," Chung reported. "Her quality of life has been reasonable, under the circumstances. Recovery from this type of radiosurgery is virtually immediate, because there are no incisions or invasive procedures and because the technology allows us to treat tumors to high doses while sparing normal organs."

Jeffrey Williamson, PhD, chairman of the Medical Physics Div. at the Massey Cancer Center Radiation Oncology Department, said, "We treat some 30 patients per day, mostly for lesions in the brain, lung or liver. I see that widening in the near future, as system enhancements help us use images to adapt the treatment plan every day over a longer course of treatment. That's what's coming next."

For more information, visit: www.massey.vcu.edu