Women diagnosed with early-stage breast cancer who have lumpectomy usually have radiation therapy after surgery. Radiation therapy after lumpectomy lowers the risk of the 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).
An ongoing study called NSABP B-39/RTOG 0413 is looking at the effectiveness and safety of three types of partial-breast irradiation and comparing them to whole-breast irradiation. Early results from the study on one type of partial-breast irradiation -- 3-D conformal external beam radiation -- suggest that the number and severity of side effects from 3-D conformal external beam radiation are low. The results were presented at the October 2011 annual meeting of the American Society for Radiation Oncology (ASTRO).
The drawbacks of traditional whole-breast irradiation include daily trips to the hospital for treatment -- usually 5 days a week for 4 to 6 weeks -- and accidentally exposing nearby healthy tissue (the lungs or heart, for example) to radiation.
To overcome these drawbacks, doctors have developed partial-breast irradiation techniques. The new techniques deliver more focused and intense radiation therapy over a shorter period of time. Because the radiation is more focused, the new techniques may cause fewer or milder side effects than traditional radiation therapy.
The three partial-breast irradiation techniques being studied in the NSABP B-39/RTOG 0413 study are:
- multi-catheter internal radiation, also called interstitial needle-catheter brachytherapy
- balloon internal radiation, known by the brand name MammoSite
- 3-D conformal external beam radiation (3DCRT)
Multi-catheter internal radiation 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.
The MammoSite system 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 2 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.
3DCRT radiation 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.
In the NSABP B-39/RTOG 0413 study, 1,458 women got 3DCRT radiation therapy. The researchers recorded how often the women had skin side effects, as well as how severe the side effects were:
- 11% of the women had moderate (grade 2 or 3) hardening or thickening of the skin (called induration); none was severe (grade 4)
- 4% of the women had moderate enlargement of small blood vessels in the skin (telangiectasia); none was severe
- 7% of the women had moderate darkening of the skin (hyperpigmentation); none was severe
- fewer than 1% of the women had moderate skin ulcers; none were severe
Because this study is large, the results suggest that 3DCRT radiation is safe. Still, NSABP B-39/RTOG 0413 will continue to study the effectiveness and safety of all three partial-breast irradiation techniques. More results will be reported in the future.
If you've been diagnosed with early-stage breast cancer and lumpectomy followed by radiation therapy will be part of your treatment, ask your doctor about the radiation therapy options that make the most sense for your unique situation, including:
- the characteristics of the cancer (size, location, lymph node involvement)
- your personal preferences (how important is having a shorter total radiation therapy treatment time?)
- the experience level and results of the doctors who will administer your radiation therapy
Together you and your doctor will make the best choice for YOU.
Visit the Breastcancer.org Radiation Therapy section to learn more about radiation therapy techniques and possible side effects.