The U.S. Food and Drug Administration (FDA) has approved FDA Approves MammoSite Internal Radiation Therapy as New Breast Cancer Treatment Option (dateline June 24, 2002) | Breast Health News | Imaginis - The Women's Health & Wellness Resource Network

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FDA Approves MammoSite Internal Radiation Therapy as New Breast Cancer Treatment Option (dateline June 24, 2002)

The U.S. Food and Drug Administration (FDA) has approved the MammoSite system to deliver internal beam radiation to breast cancer patients after the surgical removel of a breast lump (lumpectomy). Internal beam radiation, or brachytherapy, significantly reduces the amount of time required with standard external beam radiation and may cause fewer side effects. While the new treatment has not been found to be more effective than traditional radiation therapy, the FDA approval provides breast cancer patients with another, more convenient option and could reduce the number of women who have their entire breasts removed with mastectomy.

Internal beam radiation involves using radioactive "seeds" (called Iridium-192) to destroy remaining breast cancer cells after lumpectomy. With the MammoSite Radiation Therapy System, the physician inserts a special balloon catheter into the breast cavity (the cavity, or space in the breast, is created after tissue is removed during the lumpectomy). A hollow catheter is attached to the balloon, and during radiation therapy, the physician feeds a small radioactive seed through the catheter and into the balloon. The seed delivers radiation to the surrounding breast tissue Internal beam radiation may also used in other areas of the body, including the mouth, cervix, and prostate.

Because a lumpectomy involves removing only a breast lump and surrounding margin of normal breast tissue instead of the entire breast, it is possible that some cancer cells will not be removed during the surgery. Therefore, radiation therapy is necessary after lumpectomy to ensure that any remaining cancer cells are destroyed. Standard external beam radiation therapy has proven to be effective at preventing a recurrence of cancer after a mastectomy; however, the treatment can be inconvenient for women because it must be administered over a six to seven week period. With internal beam radiation therapy, treatment time is reduced to five days.

Since internal beam radiation involves exposing less breast tissue to radiation, fewer skin reactions (such as redness, rashes, or irritations) occur with the new treatment. Patients also tend to experience less irritation of healthy breast tissues. According to Proxima Therapeutics Inc., the maker of the Mammosite system, internal beam radiation may also be associated with less toxic effects, compared to standard external beam radiation therapy.

"While there are positive outcomes associated with lumpectomy followed by radiation treatment, 50 percent of eligible women with early stage breast cancer still opt for a mastectomy," said Dr. Robert Kuske, Principal Investigator of the MammoSite clinical trials, as quoted in a Proxima

Therapeutics news release. "MammoSite could make it easier for more women to consider the choice of lumpectomy and provides physicians with an important new tool for the practice of breast conservation therapy."

Despite the FDA approval, internal beam radiation therapy has not been proven to be more effective at destroying cancer cells or preventing a cancer recurrence than standard external beam radiation. Further clinical trials will likely compare the two treatments more closely. However, for women with small breast cancers, internal beam radiation is a new option that women can now discuss with their physicians. The new treatment may also attract those breast cancer patients who refuse to undergo standard radiation therapy.

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