A new form of radiation therapy may prove more effective for patients undergoing surgery for locally advanced colorectal, gynecologic and renal cancers. The Mobetron, one of only seven FDA-approved mobile Intraoperative Electron Radiation (IOERT) machines, can be brought directly to the patient's operating room at the time of surgery.

Cancer patients treated with the new device receive a powerful, concentrated beam of electron radiation delivered directly to cancerous tumors while the tumors are exposed during surgery. Traditional external radiation therapy poses the risk of irradiating and causing serious damage to healthy tissues in cases where the cancerous tumors are located deep within body cavities that are surrounded by healthy tissue.

A single dose of the intraoperative electron radiation is equivalent to two to five weeks of daily external radiation therapy (10 to 25 daily radiation treatments).

IOERT is used in conjunction with a course of external radiation given prior to surgery, and surgical removal of as much of the tumor as possible. During the IOERT procedure, the surgeon can move healthy organs out of the radiation field to prevent damage, which enables a stronger dose of electron radiation to be directed to the cancerous tumor.

"Currently, we are using this new technology to treat certain disease sites, including gastrointestinal (colorectal, pancreatic, esophagus, stomach, biliary), gynecologic, renal, and head/neck cancers and sarcomas (soft tissue cancers)," says Leonard L. Gunderson, M.D., head of Radiation Oncology at Mayo Clinic Scottsdale. "As we progress with IOERT, we will begin to apply this new technology to additional disease sites, including breast and lung cancer."

Recent studies from Mayo Clinic in Rochester (Minn.), show that patients with locally advanced primary colorectal cancer who received IOERT as a component of their treatment had a 46 percent five-year survival rate compared to 24 percent in a control group without IOERT. The study also found that patients with locally recurrent colorectal cancer who received IOERT had a 19 percent five-year survival rate compared to only 7 percent who did not receive the treatment.

"IOERT enables our team of specialists to maximize the dose of radiation given to the tumor while minimizing the amount of radiation damage to surrounding normal tissue, said Gunderson. "Now, we can focus concentrated beams of radiation on cancerous tumors while they are exposed during surgery."

SOURCE:
The Mayo Clinic (http://www.mayo.edu)