Women diagnosed with early-stage breast cancer who have lumpectomy usually have radiation therapy after surgery. Radiation therapy after lumpectomy lowers the risk of breast cancer coming back (recurrence) and makes lumpectomy as effective as mastectomy.
There are two basic ways to deliver radiation. The traditional way is to irradiate the entire breast (whole-breast irradiation) with radiation from an external source. Newer methods deliver radiation internally, or externally in precisely focused three dimensions, to just the area of the breast where the cancer was (partial-breast irradiation). Internal partial-breast irradiation also is called brachytherapy.
A study has found that older women who have brachytherapy after lumpectomy are more likely to have a mastectomy 5 years after surgery compared to women who had traditional external beam radiation therapy. Still, women who got either type of radiation therapy had better outcomes than women who got no radiation after lumpectomy.
The study was published in the February 2014 issue of the International Journal of Radiation Oncology*Biology*Physics. Read the abstract of “Benefit of Adjuvant Brachytherapy Versus External Beam Radiation for Early Breast Cancer: Impact of Patient Stratification on Breast Preservation.”
More women and their doctors are choosing brachytherapy after lumpectomy instead of external beam radiation therapy. This may be happening for a number of reasons, including scheduling convenience.
Traditional external beam radiation therapy requires daily trips to the hospital for treatment -- usually 5 days a week for 4 to 6 weeks.
Brachytherapy uses radioactive “seeds” to deliver radiation directly to the area where the cancer was. The seeds are placed in very small tubes that are stitched into place under the skin. The seeds are left in the tubes for a few hours or a few days. You stay in the hospital during treatment. Once the treatment is done, the seeds, tubes, and stitches are removed and you go home.
Other studies have suggested that older women who have brachytherapy after lumpectomy were more likely to have treatment complications as well as need a mastectomy in the 5 years after lumpectomy compared to women who had external beam radiation. Because results on the effectiveness of brachytherapy have been mixed, the American Society for Radiation Oncology (ASTRO) has proposed guidelines on who would most benefit from brachytherapy. In this study, the researchers wanted to scientifically validate those guidelines.
Among other criteria, the ASTRO guidelines say that women who would most benefit from brachytherapy are 60 or older and have been diagnosed with cancer that:
- is 2 cm or smaller in size
- is hormone-receptor-positive
- has a low risk of recurrence
- has negative margins (no cancer was found in the tissue around the cancer that was removed during surgery)
- is node-negative (no cancer was found in the lymph nodes)
These women are classified as “suitable” for brachytherapy.
ASTRO also has a “cautionary” classification for brachytherapy. Among other criteria, these women are ages 50 to 59 and have been diagnosed with breast cancer that:
- is 2.1 cm to 3.0 cm in size
- is hormone-receptor-negative
Women considered “unsuitable” for brachytherapy by ASTRO are younger than 50, have an abnormal BRCA1 or BRCA2 gene, and have been diagnosed with breast cancer that is:
- larger than 3 cm in size
- has positive margins
- has spread to the lymph nodes
Using information from SEER, a large registry of cancer cases from sources throughout the United States maintained by the National Institutes of Health, the researchers looked at the health records of nearly 36,000 women diagnosed with breast cancer from 2002 to 2007. All the women were older than 65:
- 28,718 women were diagnosed with invasive breast cancer
- 7,229 women were diagnosed with DCIS
Most of the women had external beam radiation therapy:
- 26,383 women had external beam radiation therapy
- 1,310 women had brachytherapy
- 8,254 women had only lumpectomy with no radiation therapy
Overall, 5 years after lumpectomy:
- 1.3% of women who had external beam radiation therapy had mastectomy
- 2.8% of women who had brachytherapy had mastectomy
- 4.7% of women who had no radiation therapy had mastectomy
The researchers then looked to see how many women diagnosed with invasive breast cancer met the ASTRO guidelines for brachytherapy:
- 34.7% were classified as suitable
- 17.6% were classified as cautionary
- 35.2% were classified as unsuitable
- 12.5% couldn’t be classified
Overall, 55% of the women treated with brachytherapy were considered suitable by the ASTRO guidelines.
The researchers then looked to see what the later mastectomy rates were by ASTRO classification. Women considered suitable for brachytherapy by the ASTRO guidelines had about the same rates of later mastectomy (1%) as women who had external beam radiation (0.8%). Women classified as cautionary or unsuitable had much higher rates of later mastectomy.
The researchers also found that women who were treated with brachytherapy had higher rates of treatment side effects, including infection, breast pain, and fat necrosis (dead or damaged fat cells that form lumps).
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 suggest that the ASTRO guidelines are a good way to figure out who will benefit from brachytherapy, some experts say that because only older women were in the study, the results can’t be applied to all the ASTRO classifications. Other experts still feel that there's not enough evidence yet to confidently conclude that brachytherapy is as effective and safe as traditional external beam 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 tubes 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.