Two recent studies on brachytherapy for breast cancer have attracted some media attention. This week, we'll share the latest research. Today, we'll start with some basic questions. What is accelerated partial breast irradiation? What is brachytherapy? How does brachytherapy differ from other methods of accelerated partial breast irradiation?
Accelerated Partial Breast Irradiation (APBI)
Traditionally, after a lumpectomy (breast conserving surgery), the entire breast is irradiated daily, for at least five weeks. The procedure is known as external beam whole breast irradiation (WBI).
Advances in technology have given rise to more convenient, more focused radiation options. For example, treatment duration can be shortened with accelerated hypofactionated whole breast radiation, which delivers higher doses of radiation over a shorter period of time, generally about three weeks. Another option, external beam partial breast irradiation, delivers radiation to a specific area of the breast, rather than the entire breast.
The term 'accelerated partial breast irradiation (APBI)' refers to treatment options that both shorten treatment time (accelerated) and treat a specific area of the breast (partial breast).
There are several different methods of APBI. For example, intraoperative radiotherapy treats the tumor cavity with radiation during surgery. The INTRABEAM sytem is a type of intraoperative radiotherapy. 3D conformal radiation therapy (3-D CRT), on the other hand, is a type of external beam APBI.
Brachytherapy refers to any APBI technique which supplies radiation directly to the tumor cavity within the breast after surgery. This is typically accomplished with the use of catheters containing radioactive seeds, like those pictured above. Treatment takes about a week.
There are several different types of brachytherapy.
Interstitial brachytherapy involves the insertion of several individual catheters for radiation delivery. (See image to the right.)
Several newer techniques involve one point of entry. For example, Mammosite (image below, left) and the Contura Multi-Lumen Balloon (image below, center) methods deliver radiation via an applicator with a balloon tip. After insertion through an incision, the balloon tip is "inflated" with a saline solution to fill the cavity the tumor occupied. A radioactive seed is sent to the balloon via a catheter system.
The SAVI Applicator (image below, right) delivers radiation via several catheters which are connected in a wisk-shaped device, which may open and close for ease of insertion.
Brachytherapy in the news
Two recent brachytherapy studies made headlines. Part 2 of this blog will focus on a presentation at the 2011 San Antonio Breast Cancer Symposium which compared mastectomy rates for brachytherapy and whole breast irradiation. Part 3 will highlight a study in the Journal of the National Cancer Institute which evaluated the use of brachytherapy in different patient populations.
Until then, links may be found on the brachytherapy page of our LATESTBreastCancer.com website. From the home page, click the Treatments tab, then search for 'brachytherapy' in the search box in the upper right corner.