Brachytherapy Pros & Cons

Brachytherapy refers to the implantation of radioactive material directly into various malignancies. Brachytherapy has been used to treat many types of cancer for decades. It has been used to treat breast cancer as a “booster treatment” after standard external beam radiation for the past 25 years. Over the past 10 years, brachytherapy has been used on its own as a treatment of localized breast cancer.

With brachytherapy, therapy is quicker than traditional forms of radiation management; the entire course being given over a five-day period with treatments twice a day. Brachytherapy only treats a portion of the breast and, therefore, the cosmetic results may be better because the majority of the breast is not radiated and remains healthy not only in appearance, but also to the touch. Finally, there appears to be no sacrifice in the chance of controlling the breast cancer locally, or any disadvantage in the chance of survival, at least in the ten-year follow-up that we now have.

There are two popular ways of administering brachytherapy to the breast. In the first method – around for decades -- several hollow nylon tubes are inserted under local anesthetic into the affected portion of the breast. These tubes are after-loaded with high-dose Iridium 192 isotope for approximately five minutes twice per day over a five-day period. This type of irradiation delivers an extremely even dose of radiation across the affected area, while sparing healthy tissue.

The second, newer form of Brachytherapy – called MammoSite™ – uses one catheter with a balloon and one single high-dose Iridium source placed as the center of the biopsy cavity. The advantages of the MammoSite procedure are its simplicity in administration. The disadvantage is that there is no way to confine the dose to the portion of the breast being treated. All patients receive the same dose distribution. If a woman has a small tumor in the center of a large breast, the MammoSite dose distribution appears to be acceptable. In smaller breasts, the MammoSite may actually deliver the same dose to the skin and lung as to the tumor bed, negating the advantages of brachytherapy by not sparing normal tissue.

Breast brachytherapy for localized breast cancer is not for everyone. The best candidates are those women with fewer than four positive lymph nodes and solitary tumors less than 5 cm in diameter that have been completely surgically removed. Some physicians will not perform brachytherapy on patients who have any positive lymph nodes, although many physicians will still perform this procedure as long as the woman is receiving chemotherapy and has fewer than four positive lymph nodes. The final advantage of brachytherapy is that it can be delivered very soon after the lumpectomy and lymph node sampling is performed. In other words, radiation can be completed before chemotherapy starts, if chemotherapy is recommended.

With brachytherapy, the local treatment has already been completed and, when chemotherapy is over, all treatment is finished. For patients who live in rural areas or live far from their hospitals, it may be difficult to go in for daily radiation treatments.

This article is excerpted from the winter 2004 issue of Lifeline.