A seven-year-old breast-cancer treatment procedure that places a radioactive "seed" inside the breast rather than beaming radiation into it is gaining in use here, though it's viable for only a portion of breast-cancer patients, providers here say.
The procedure, called MammoSite, is used following a lumpectomy that involves removal of a cancerous tumor, and is one of a handful of follow-up treatment options such as chemotherapy, beamed-radiation therapy, and hormonal therapy. A lumpectomy and the follow-up therapies are an alternative to a mastectomy, which is the removal of an entire breast.
MammoSite is touted for its ability to target the area where radiation therapy is needed more closely than if a radiation beam is used, and because it enables patients to make fewer trips to a cancer center to receive it than if other follow-up treatment options are used, providers say.
"It's becoming more and more accepted," says Dr. Carol Guthrie, director of the breast section of Providence Regional Cancer Center at Providence Sacred Heart Medical Center & Children's Hospital here. "Like many new procedures in medicine, the increased use and popularity and public demand sometimes outpace scientific data."
The MammoSite technology, owned by Bedford, Mass.-based Hologic Inc., uses a catheter system with which a surgeon inserts a balloon-tipped catheter into the patient's breast to reach the exact location where the cancerous tumor was removed, then inflates the balloon with saline solution, filling the cavity left by the removed tumor. A radiation oncologist then guides a radioactive seed into the balloon, where it delivers radiation to the surrounding tissue. The seed typically remains in the breast for approximately 10 minutes before it's removed. The process is done twice a day for five days. The catheter remains in place during the five days.
Radiation therapy following a lumpectomy conventionally has been done by aiming an external beam of radiation at the cancer site in a breast, subjecting surrounding tissue to radiation.
With MammoSite treatment, "We haven't seen any complications, and it's been really beneficial," says Dr. Karie-Lynn Kelly, a radiation oncologist at Kootenai Cancer Center, in Coeur d'Alene, one of three cancer-care facilities in Kootenai County operated by Kootenai Health. "It's really good for women who live a fair distance away" from where their radiation treatment would take place, because the treatment takes only days instead of weeks, she says.
As with external-beam radiation treatment, the patient doesn't spend the night in the hospital.
Providence's Guthrie says that since October 2006, the cancer center at the large Spokane hospital has completed MammoSite radiation therapy 190 times.
"The advantage is that, theoretically, MammoSite delivers radiation to the site where it is most needed, sparing surrounding healthy tissue like skin, bones, lungs, ribs, (and the) heart," she says. "The cosmetic results were expected to be superior to external radiation. It appears to be true, but long-term data are not available."
The Kootenai Cancer Center began providing MammoSite radiation therapy eight months ago, and so far has been averaging one patient per month, Kelly says. The cancer center treats about 100 patients a year with external-beam radiation therapy, she says.
External-beam radiation therapy usually is done over about six weeks and can provide risk to organs, providers say.
Allison Benjamin, a spokeswoman for Cancer Care Northwest, of Spokane, says, "It's being utilized more frequently as national treatment data becomes more mature and continues to show excellent outcomes for specific patients. National and international reports continue to show favorable patient cure rates and cancer-free rates."
Benjamin says, however, that MammoSite is used far less frequently than external-beam radiation therapy because fewer women are candidates for it.
"It is an option for approximately 20 percent of our patients, but ultimately is chosen in about 5 percent of patients who receive a lumpectomy," she says.
Kelly says MammoSite candidates typically are women who are at least 45 years old, who have tumors smaller than three centimeters in diameter, and whose tumors haven't spread to lymph nodes and are at least one to two centimeters below the surface of the skin.
Dr. Renu Sinha, a breast surgeon at Rockwood Clinic, of Spokane, says MammoSite radiation therapy may be as effective as whole-breast radiation therapy in certain women, because the tumors tend to return to the same area of the breast.
"We don't know the long-term outcome of partial-breast radiation," Sinha says. "It's not standard of care just yet."
Some women choose to have a full mastectomy because they don't want to go through the several-week-long treatment schedules of external-beam radiation therapy and want to avoid the risks that any radiation therapy can pose, she says.
"It's just the hassle factor," Sinha says. It's inconvenient and expensive for patients who don't live in Spokane or Coeur d'Alene to stay for weeks to go through external-beam radiation treatment.
On the other hand, because MammoSite therapy takes days instead of weeks, "More patients are asking about it," Sinha says.
Unlike external-beam radiation therapy, MammoSite requires an invasive procedure in the placing of the catheter and balloon. Guthrie says one of the disadvantages is the occasional need to remove the balloon before the treatment is completed, usually if the surgeon has trouble getting the balloon to conform to the shape of the cavity or if an infection is found.
MammoSite appears to cause less fatigue in patients than external-beam radiation, and causes less of a skin reaction, Kelly says.
Guthrie estimates that at Providence's cancer center here between 50 percent and 75 percent of women who are candidates for MammoSite choose to have it. Providence's cancer center has seven radiation oncologists, and two of those do the majority of the MammoSite treatments.
The therapy is done in Providence's radiation oncology department at Sacred Heart, she says.
At Kootenai Cancer Center, one of two radiation oncologists teams up with a surgeon to perform a MammoSite procedure, Kelly says. The surgeon removes the tumor and places the catheter and balloon in a breast, and the radiation oncologist delivers the first seed radiation therapy once the lumpectomy is completed.
Providers give different answers on whether MammoSite costs more or less than external beam radiation therapy.
Benjamin says MammoSite is just one type of breast balloon brachytherapy, or implant therapy, device.
Separate from MammoSite is what's called the Contura balloon device, she says. While MammoSite uses a single catheter to deliver radiation from a seed, Contura is a multi-channel device with five catheters.
After being inserted, the Contura balloon is inflated and filled with saline and then a vacuum is used to help the balloon fit closely within the often irregularly-shaped lumpectomy cavity, she says. A single radiation seed is sent through five separate channels inside the balloon, allowing the radiation dose to be contoured to reach the targeted area.
The dose is directed by where the seed sits in the balloon, allowing the physician to concentrate the radiation dose on the tumor area. With the multichannel design, more accurate treatment is achieved, she says.
Cancer Care Northwest, which has been doing MammoSite therapy since 2003, has three radiation oncologists with specialized training for delivering radiation doses internally to the breast lumpectomy cavity and the surrounding adjacent tissues.
It has four surgical oncologists with experience in performing lumpectomies and placing the MammoSite and Contura devices, Benjamin says. The surgeries are done at Cancer Care Northwest's south Spokane office, at 601 S. Sherman; its Spokane Valley office, at 12615 E. Mission; and its downtown office, at 910 W. Fifth, at Deaconess Medical Center. Cancer Care Northwest does the radiation therapy at its Deaconess office, she says. She declines to say how many MammoSite procedures Cancer Care Northwest has performed.
"I can say that we have performed many of these procedures for the right candidates," she says.
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