Brachytherapy, a form of radiation treatment, has been offered as an alternative to and in conjunction with traditional radiation treatment for some time. Used as therapy for many different types of cancer including prostate cancer, brachytherapy has generally been used in cases of breast cancer where the patient has decided to undergo a lumpectomy rather than a mastectomy. Because a lumpectomy only removes the cancerous tumor within the breast and leaves the rest of the breast intact, there is a chance that cancer may recur in the cells near the margins of tumor excision. To combat these cancerous cells, radiation therapy is often used to destroy any cancer cells that may still exist in the breast.
Traditional radiation therapy consists of daily or weekly radiation treatment to the outside of the breast area for a period of up to 6 months. In contrast to traditional radiation treatment, brachytherapy employs the use of radiation from the inside of the body through a set of 10 – 15 catheters, rather than radiation applied to the outside of the affected breast. The catheters remain in the body for one week while a series of 5 to 10 radiation treatments are conducted. During therapy, a radioactive seed (Iridium-192) is placed within the catheter producing a radioactive beam for no longer than 15 minutes. Though the process itself is painless, the insertion of the catheters is highly invasive. MammoSite, approved by the FDA in May 2002 is a less invasive form of brachytherapy. Instead of employing multiple catheters, MammoSite requires the insertion under local anesthetic of one catheter and a balloon into the cavity where the lumpectomy was performed. A radioactive pellet is attached to a wire which is inserted into the catheter and the balloon. A specific amount of radiation is delivered to the surrounding breast tissue twice a day for a period of five days.
Due to the short treatment length of brachytherapy over traditional radiation therapy, chemotherapy can also be utilized sooner if radiation therapy is conducted first. Dr. Robert Kuske of the Univ. of Wisconsin at Madison notes that “There is an 8 week delay in chemotherapy if external beam [traditional] radiation is given first and there is typically a 3.5 month delay if external beam radiation is given after chemotherapy.” Because research has proven that radiation therapy completed without delay is most effective, brachytherapy offers some promising results.
Furthermore, because the treatment is conducted from inside the body and is focused on the area of lumpectomy, areas such as other parts of the breast, lungs and heart are not treated. This also results in a smaller surface skin burn and scar possibility that is generally associated with traditional radiation therapy.
While brachytherapy has not been found to be more effective than traditional radiation therapy, proponents of breast conservation treatments in breast cancer regard brachytherapy as an important option for women contemplating a lumpectomy over a mastectomy. According to Dr. Kuske, “50 percent of eligible women with early stage breast cancer still opt for a mastectomy” based on the fact that time constraints due to family and work render traditional radiation therapy logistically impossible. “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.”
MammoSite and brachytherapy are recommended for tumors smaller than 2 cm and the shape and size of the cavity created by the lumpectomy must also be taken into consideration. Further clinical trials must be completed to determine the long-term efficacy of the treatments.