Fact Sheet - Mobile Intraoperative Electron Irradiation (IOERT)

Thursday, May 30, 2002

Locally advanced cancers can be radiated during surgery with Intraoperative Electron Radiation (IOERT), an advanced radiation treatment now available at Mayo Clinic Hospital in Phoenix. IOERT is delivered to cancers that cannot be safely removed by the surgeon, or to the tumor bed, a narrow area surrounding the tumor removal site.

This is breakthrough treatment because many institutions do not offer curative treatment options for patients with locally recurrent cancers

· The FDA-approved mobile Intraoperative Electron Radiation (IOERT) machine, called the "Mobetron," can be brought directly to the patient's operating room at Mayo Clinic Hospital where a team delivers a concentrated beam of electron radiation directly to cancerous tumors while they are exposed during surgery.

· Mayo Clinic Hospital is the only location in the Southwest, and one of only seven centers in the world, with this new treatment option.

· Studies show that when IOERT is delivered in conjunction with external radiation, surgical removal of as much cancerous tissue as possible and effective systemic treatment (such as chemotherapy), it improves local tumor control and survival rates for patients with various types of locally advanced and recurrent cancers.

· Currently the Mayo Clinic Cancer Center Scottsdale uses IOERT to treat certain disease sites including gastrointestinal (colorectal, pancreatic, esophagus, stomach, biliary), gynecologic, renal and head/neck cancers and sarcomas. In the future, this technology will be applied to additional disease sites, including breast and lung cancer.

· When conventional external radiation is used alone in the treatment of locally advanced cancers that cannot be surgically removed, the dose of radiation needed to control the cancer often exceeds the tolerance of surrounding normal tissues and organs, causing damage to healthy tissue.

· With IOERT, the surgeon can move normal organs out of the IOERT field to prevent damage to healthy tissue and to enable a stronger dose of electron radiation to be directed to the cancerous tumor or tumor bed.

· A single dose of IOERT is equivalent to two to five weeks of daily external radiation therapy (i.e. 10 to 25 daily external treatments).

· Statistical data for IOERT includes:

· Recent studies at 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 the 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 seven percent for patients who did not receive IOERT.

· Mayo Clinic studies of locally recurrent gynecologic and renal cancers and abdominal-pelvis sarcomas show that 25 to 40 percent of patients who received IOERT as a component of treatment were five-year survivors. Many institutions do not offer curative treatment options for patients with locally recurrent cancers. · Leonard L. Gunderson, M.D., chair of the Department of Radiation Oncology and deputy director for Clinical Affairs at Mayo Clinic Cancer Center - Scottsdale, joined Mayo Clinic Scottsdale in 2001. He was a pioneer in the development of IOERT at Mayo Clinic in Rochester, Minn., and at Massachusetts General Hospital and Harvard Medical School.

· More than 1,500 patients have been treated with intraoperative electron irradiation at Mayo Clinic in Rochester, Minn., since 1981, making it the largest IOERT program in the world.

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