In a presentation to the Radiological Society of North America, Robert R. Kuske, M.D., a radiation oncologist with Arizona Oncology Services, discussed accelerated partial breast irradiation (APBI), also known as brachytherapy.

According to Kuske, approximately 80 percent of women diagnosed with breast cancer are candidates for breast conservation therapy, in which the lump is surgically removed and any remaining cancerous cells are destroyed by radiation therapy, leaving the breast intact. Unfortunately, despite 20 years of studies demonstrating no difference in survival rates between women receiving mastectomy or lumpectomy followed by radiation therapy, only 55 percent of women opt for the latter treatment.

Kuske cited two major reasons breast cancer patients avoid breast-saving radiation treatments. "I believe women choose mastectomy because of the inconvenience of six to seven weeks of conventional external beam radiation therapy (EBRT) and the fear of whole-breast irradiation to uninvolved breast, skin, ribs, lung and the heart."

Kuske has led three trials investigating brachytherapy, a technique that eliminates those barriers. Brachytherapy involves placing a tiny radioactive seed inside the breast, up against the tissues harboring the breast cancer. Since the radiation is directed to the 1 to 2 centimeters of breast surrounding the lumpectomy site, the rest of the breast and surrounding organs are spared, and the entire radiation treatment takes only four to five days. These trials have shown low toxicity and cancer recurrence rates of only 3 to 4 percent in the breast.

Two brachytherapy methods are currently used to place radiation into the treatment area: interstitital brachytherapy, which involves multiple catheters (thin, hollow plastic tubes) around the surgical excision site, or a single balloon catheter that is inserted and then inflated in the lumpectomy cavity. Compared to EBRT, brachytherapy intensely treats the part of the breast that is at the greatest risk for a recurrence of cancer with minimal radiation exposure to the rest of the breast, heart, lungs and skin.

Women are eligible for breast brachytherapy if their tumor size is 3 centimeters or smaller as long as the cells do not reach the surgical margin. Up to three lymph nodes under the arm may be involved.

"Brachytherapy makes breast conservation therapy more convenient for women located in rural areas and for those who have busy lifestyles or occupation that will not accommodate up to seven weeks of radiation treatment," Kuske said.

SOURCE:
Radiological Society of North America (http://www.rsna.org)