Radiation therapy commonly is used after lumpectomy to treat early-stage breast cancer and reduce the risk of the cancer coming back (recurrence). Brachytherapy is a newer form of radiation therapy and an alternative to traditional whole-breast external beam radiation therapy. Brachytherapy delivers a higher dose of radiation to a smaller area of the breast over a shorter period of time compared to traditional external beam radiation therapy. Doctors sometimes call brachytherapy accelerated partial-breast irradiation (APBI).
Brachytherapy use increased steadily in the United States since it was first approved by the U.S. Food and Drug Administration in 2002. But since 2008, using brachytherapy after lumpectomy has slightly declined. Many experts were concerned about the increase because there haven’t been many long-term studies showing that brachytherapy works as well as traditional radiation therapy.
A small study with 10 years of follow-up information suggests that brachytherapy is as effective as whole-breast radiation at preventing breast cancer recurrence.
The study was presented on Sept. 8, 2013 at the 2013 Breast Cancer Symposium. Read the abstract of “Ten-year outcomes of accelerated partial breast irradiation compared with whole breast irradiation; A matched-pair analysis.”
Traditional external beam radiation therapy aims cancer-destroying energy at the whole breast or to the area of the breast where the cancer was. The source of the radiation is outside the breast, which is why it's called "external beam." Many studies have shown the long- and short-term effectiveness of external beam radiation therapy. The drawbacks of traditional radiation therapy include daily trips to the hospital for treatments -- typically 5 days a week for 4 to 6 weeks. Traditional radiation therapy also has a large field and may expose healthy tissue, such as the heart and lungs, to radiation.
To overcome the drawbacks of traditional radiation therapy, doctors have developed different ways to deliver radiation. Brachytherapy places the radiation source inside the breast. Two types of brachytherapy are used right now and another is experimental. They are:
- Multi-catheter internal radiation, also called interstitial needle-catheter brachytherapy. This approach uses radioactive "seeds" to deliver radiation directly to the area where the cancer was. The seeds are placed in very small tubes (catheters) that are stitched into place under the skin. The seeds are left in the tubes for a few hours or a few days. You remain in the hospital during treatment. Once the treatment is completed, the seeds, tubes, and stitches are removed and you go home.
- Balloon internal radiation, known by the brand name MammoSite. This approach places a special tube with a balloon on one end in the breast where the cancer was. The tube comes out of the skin through a small hole. The tube and balloon are placed either during lumpectomy or afterward in a surgeon's office. During each treatment, a machine places a radioactive seed into the center of the balloon for 5 to 10 minutes -- just long enough to deliver the required dose of radiation. After the seed is removed, you may leave the treatment center. A total of 10 treatments are usually given over 5 days. That means two treatments per day, about 6 hours apart. When the final treatment is done, the balloon and tube are removed through the small hole in the skin.
- 3-D conformal external beam radiation (3DCRT). This experimental approach starts with a planning session (simulation). A special MRI or CAT scan of the breast is done and is used to map out small treatment fields for the area at risk. The type and distribution of radiation is designed to maximize the dose to the area that needs to be treated and avoid or minimize radiation to tissue near the area. The radiation is delivered with a linear accelerator, the same machine used in traditional external radiation, twice a day for 1 week.
To see if brachytherapy offered the same outcomes as traditional whole-breast radiation, the researchers compared the records of 247 pairs of women diagnosed with early-stage breast cancer who had lumpectomy. One woman in each pair had traditional whole-breast radiation and the other woman had brachytherapy, either multi-catheter internal radiation or balloon-internal radiation.
The women were matched in terms of:
- size of the cancer
- estrogen receptor status
Still, there were some differences between the women who got brachytherapy and the women who got whole-breast radiation:
- women who had whole-breast radiation were more likely to have cancer in the lymph nodes (14% compared to 9%) and were also more likely to have been treated with hormonal therapy (68% compared to 54%) compared to women who got brachytherapy
Half the women were followed for more than 8 years and half the women were followed for shorter time periods.
The researchers found that rates of:
- local recurrence (the breast cancer coming back in the same breast)
- contralateral recurrence (breast cancer being diagnosed in the opposite breast)
- regional recurrence (breast cancer coming back in the chest wall or lymph nodes)
- disease-free survival (how long the women lived without the cancer coming back)
- overall survival (how long the women lived whether or not the cancer came back)
- complications, such as infection or breast pain
were about the same for women who had brachytherapy compared to women who had whole-breast radiation.
Besides being a quicker way to deliver radiation therapy, many doctors like brachytherapy because the radiation delivery is focused, potentially avoiding exposing healthy tissue to radiation. While the results of this study are promising, some experts question whether the pairs of women were really well matched because the women who had whole-breast radiation were more likely to have been treated with hormonal therapy. Other experts continue to warn that right now there's not enough evidence to confidently conclude that brachytherapy is as effective and safe as traditional whole-breast radiation therapy, though more study results are expected to be published soon.
If you've been diagnosed with early-stage breast cancer, are having lumpectomy, and will be receiving radiation therapy after surgery, you and your doctor may consider brachytherapy as an alternative to traditional external beam radiation therapy. Perhaps the daily trips to the treatment center would be a burden because of distance. Talk to your doctors about their experience with brachytherapy compared to traditional radiation therapy. You also may want to ask about their familiarity with the technical aspects of delivering brachytherapy since placement of the catheters or balloon is a skill that can take some time to master.
The Breastcancer.org Radiation Therapy section has more information on both traditional external beam radiation therapy and brachytherapy.