Hammond, 33, and the mother of three children, was diagnosed with breast cancer in August 2011. Doctors later discovered the cancer had spread to her lymph nodes.
"We dived right in with chemotherapy," she said. Hammond, who lives in Arlington, was treated at Providence Regional Cancer Partnership in Everett.
The tumor was in her left breast. But doctors also spotted a "place of interest" in diagnostic scans of her right breast. So in February, she had surgery to remove both breasts, rather than chance having a second breast cancer battle.
Before beginning the third step in her treatment, radiation, she talked to doctors at the Seattle Cancer Care Alliance.
She met with Dr. Janice Kim, a radiation oncologist, where she learned of a technology used with prostate cancer patients that was now being applied in the treatment of breast cancer patients.
The machine uses tiny transmitters about the size of a grain of rice, which are taped to the chest. They act like mini GPS systems to pinpoint the exact position of the breast during radiation treatments.
Accuracy is especially important for patients with cancer in the left breast. The heart can sit right up against the rib cage, so it can unintentionally be hit with the radiation beams intended to kill any of the breast's remaining cancer cells.
The goal is for the radiation beams to hit the entire breast, minimizing the heart's exposure to radiation.
If a portion of the heart, such as a coronary artery, is exposed to radiation, those vessels can react by constricting -- similar to the narrowing caused by cholesterol. "The same treatment that can potentially cure you can potentially cause long-term problems," Kim said. "As a radiation oncologist . . . I'd love to be part of the cure, but would hate to give them a higher likelihood of heart attack or heart failure as a tradeoff."
For radiation, accuracy is the key, she said. Adjustments as small as one-eighth of an inch can be made to help assure the radiation is aimed precisely.
Simply asking patients to hold their breath during radiation treatments will move the breast farther forward and push the heart down and away from the breast by as much as several inches, Kim said.
The tiny electronic transmitters can help detect both when the patient is positioned perfectly for radiation and that the patient is holding her breath during each radiation segment, which typically lasts about 30 seconds.
The transmitters can provide updated tracking information 10 times a second, said Ed Vertatschitsch, general manager of Real Time Tracking Technologies, and who helped develop the units.
The technology, called Calypso, costs about $500,000 and works in conjunction with the linear accelerators that deliver the radiation treatments.
Hammond, who began her radiation treatments in April, is one of about 35 patients treated this year using the tracking technology.
"We're getting a lot of calls from around the country," Kim said. Information on adapting the technology for breast cancer patients will be presented at a national breast cancer symposium in San Antonio in December.
Madigan Army Medical Center and a radiology group in Sacramento also are using the Calypso technology with breast cancer patients.
In Everett, Providence Regional Cancer Partnership has used a different technology for the past four years with the same goal -- protecting the heart from unwanted radiation, said Dr. Will Wisbeck, medical director of radiation oncology.
The breath monitoring and radiation pinpointing technology is built into an integrated system that also sends radiation to the breast.
"There's a number of techniques to try to exclude the heart from the radiation field," he said.
As cancer treatment has become more effective, cure rates are higher, Wisbeck said. "There's a new emphasis on decreasing the side effects and risks of treatment."
When using the heart-protecting technology, a two-minute dose of radiation is broken into 20- to 30-second segments, he said, the period of time patients can comfortably hold their breath.
The mini GPS system used at the Seattle Cancer Care Alliance is part of California-based Varian Medical Systems, the maker of the radiation monitoring and delivery system used by the Providence cancer center in Everett.
The two systems use different methods to accomplish the same goal, said Meryl Ginsberg, a Varian spokeswoman.
In 2007, Swedish Cancer Institute in Seattle, part of Swedish Health Services, said it was the first cancer center in the world to use the radiation guidance technology for prostate cancer patients.
The tiny transmitters are inserted into the prostate gland. "It was very useful in that setting," Kim said. The bladder and rectum are both close by, which can move slightly during normal functioning.
As with radiation of the breast, "you don't want a moving target during radiation," Kim said.
The Calypso technology eventually could be used anywhere in the body, Ginsberg said. Studies are being conducted at six sites, including three in the United States, to test the effectiveness of the tiny units being implanted in the lungs of lung cancer patients, Vertatschitsch said.
Doctors at the Seattle Cancer Care Alliance talked for several years about how the technology could be adapted to breast cancer patients, Kim said. They didn't want the transmitters to be inserted into the breast because the units, made out of metal, could interfere with breast imaging technology.
Eventually, the L-shaped transmitters were developed that could be taped to the chest.
If the patient moves, or even sneezes, the radiation can be stopped "and then started right back up again," Kim said.
Hammond had to commute from her home in Arlington to Seattle every weekday for 21 radiation treatments, which were completed in May.
"It was definitely worth it," she said. Tests conducted before the radiation showed that when she took a deep breath "my heart pretty much disappeared" from the radiation's projected path.
"That was very exciting," she said. "It's kind of scary to think about the harmful effects later in life . . . I just didn't want to gamble with it."
Sharon Salyer: 425-339-3486; email@example.com.
Join the fight
Making Strides Against Breast Center, a American Cancer Society fundraising 5-kilometer walk, is scheduled from 9:30a.m. to 11 a.m. Sunday The event begins at the Snohomish County Courthouse Plaza, 3000 Rockefeller Ave. in Everett.
For more information, contact the Everett American Cancer Society firstname.lastname@example.org or call 425-741-8949.
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