What Is a Radiation Boost For Breast Cancer?

Radiation Boost Side Effects and Recurrence Benefits

What is a radiation boost for breast cancer?. Istockphoto.com/Stock Photo©Jovanmandic

What is a radiation boost for breast cancer and what do I need to know?

A Radiation Boost - "A Little Extra" At The End of Radiation

Early-stage breast cancer is often treated with a lumpectomy or mastectomy and radiation therapy. Even though the tumor may have been small and no metastases were found, women and their doctors still look for ways to prevent a recurrence. The technique of giving a radiation boost at the end of treatment has been very effective in keeping breast cancer from coming back.

A radiation boost is one or more extra treatments targeted at the tumor bed.  This extra dose covers a small area and affects the tissue where cancer is most likely to return. Radiation boost treatments are given after the regular sessions of radiation are complete. Women who are 40 years old or younger at time of treatment get the most benefit from a radiation boost, but patients of all ages will have a lower risk of recurrence if they receive a booster treatment.

How is a Radiation Boost Given?

Breast cancer patients may have whole breast radiation (WBI) or partial breast radiation (given with external beams or brachytherapy), after which boost doses are given. If you're having a lumpectomy and are planning on radiation, surgical clips may be placed at the time of surgery, to help your radiation oncology team target your tumor bed during treatment. Your boost dose may be given with external radiation, via interstitial catheters, or from within a brachytherapy applicator.

The targeted boost dose may be given in one session, or during five to seven daily sessions.

Effect of Risk of Recurrence with Early Stage Breast Cancer

After being diagnosed with breast cancer, the first decision you may face is whether to have a lumpectomy or a mastectomy. You have to weigh that decision with the fact that breast cancer is most likely to recur in the same breast, right at the tumor site.

Many women opt to remove the whole breast, in hopes of never having breast cancer come back. A radiation boost is designed to prevent recurrence at the tumor site, even after a lumpectomy. Research has shown that women who had a radiation boost had fewer local recurrences - up to 50% less - when compared to those patients who didn't have the boost. Doctors hope that, because of better radiation techniques, more women will be able to choose lumpectomy over a mastectomy, and have a better quality of life after treatment.

For patients diagnosed with early stage breast cancer, either ductal carcinoma in situ (DCIS) or invasive breast cancer, a radiation boost protects against recurrence. Most patients who have a lumpectomy will qualify for radiation with a boost, and in some rare cases, mastectomy patients may also have radiation and the boost. There is some disagreement among radiation oncologists as to whether or not a radiation boost really benefits a patient diagnosed with DCIS, but it has become the standard of care.

  It's thought that a radiation boost may decrease the need to have a mastectomy due to recurrence after a lumpectomy by 35%.

Effect on Survival

Even though a radiation boost significantly reduced the risk of breast cancer recurrence, it did not appear to have any effect on overall survival up to 20 years out.  This does not mean that a radiation boost was ineffective, as concerns in addition to survival are important for people to consider during treatment.

Side Effects of Radiation Boost

A radiation boost is generally tolerated quite well, with fatigue being the most common symptom as with conventional radiation treatments.

A radiation boost does not appear to raise the risk of complications of radiation therapy, such as infection, and did not increase the risk of secondary cancers related to the extra radiation.  Secondary cancers are cancers that arise due to the cancer causing effects of cancer treatments such as radiation.

Fibrosis is the most significant side effect of a radiation boost and radiation fibrosis can be quite annoying.  Studies have found that at 5 years, as well as at 10, 15, and 20 years post radiation boost, the risk of breast fibrosis is substantial.  Thankfully this risk is often less of a concern for younger patients.

Sources:

Bartelink, H., Horiot, J., Poortmans, P. et al. Impact of a higher radiation dose on local control and survival in breast-conserving therapy of early breast cancer: 10-year results of the randomized boost versus no boost EORTC 22881-10882 trial. Journal of Clinical Oncology. 2007. 25(22):3259-65.

Franco, P., Cante, D., Sciacero, P. et al. Tumor Bed Boost Integration during Whole Breast Radiotherapy: A Review of the Current Evidence. Breast Care. 2015. 10(1):44-9.

Moran, M., Schnitt, S., Giuliano, A. et al. Society of Surgical Oncology-American Society for Radiation Oncology consensus guideline on margins forbreast-conserving surgery with whole-breast irradiation in stages I and II invasive breast cancer, Annals of Surgical Oncology. 2014. 21(3):704-16.

Sedlmayer, F., Reitsamer, R., Russl, C. et al. Boost IORT in Breast Cancer: Body of Evidence. International Journal of Breast Cancer. 2014. 2014:472516.

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