OKLAHOMA CITY — Chemotherapy coupled with a new microwave heat therapy from OU Health Sciences Center shows success in reducing large tumors.

Because of the microwave therapy’s success in shrinking tumors, the number of women needing mastectomies, surgical breast removals, was reduced by 90 percent, said Dr. William Dooley, a researcher at the OU Cancer Institute and director of surgical oncology at OU Medicine.

“This therapy is a major advancement for women with later-stage breast cancer,” Dooley said. “Right now, most patients with large tumors lose their breast. With this treatment, along with chemotherapy, we were able to kill the cancer and save the breast tissue.”

Large tumors range in size from 1- to 1 1/2 inches and usually require a mastectomy, Dooley said.

The therapy, called focused microwave thermotherapy, is similar to that used in the Star Wars defense system. Two microwaves intersect at the tumor, becoming stronger, and focus that energy on the tumor, Dooley said.

During treatment, doctors heat the breast to about 110 degrees Fahrenheit, Dooley said.

“The microwave eats up the tumor cells much faster than it eats up the surrounding breast tissue,” he said. “We’re not exactly sure why this is. The best guess is that … tumors are saltier and have more ions in them than the breast tissue.”

The therapy will also help those with breast cancer because it will reduce the number of needed chemotherapy treatments and their toxicity, Dooley said.

Dooley is currently in the process of getting a redesigned machine approved by the Food and Drug Administration to start a new trial using the therapy on even larger cancer cells, ranging from 1 1/2- to 5 inches, he said.

Ellen Hopper, a breast cancer patient from Tuttle, Okla., participated in one of Dooley’s trials on early-stage breast cancer after doctors found a lump in her breast during a routine mammogram, she said.

Hopper decided not to undergo chemotherapy treatments but received one dose of the microwave therapy before her lumpectomy, the surgical removal of her lump, she said.

“I am very proud to say that I am an eight-year survivor of breast cancer, thanks to Dr. Dooley,” Hopper said.

Although Hopper’s cancer was caught early and she did not need a mastectomy, she said she thinks the new therapy is important because it saves breasts and helps women feel better about their image and body.

Hopper is also a registered nurse at OU Medical Center.