Are Radiation Boosts Necessary?

What to Expect When Undergoing a Radiation Boost

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A radiation boost for breast cancer is exactly what the name suggests—an extra radiation dose given after the regular sessions of radiation are complete. The goal of this boost is to minimize the chances of a breast cancer returning.

There are certain guidelines that outline who would benefit most from a radiation boost, so it may not be part of everyone's treatment. There is some evidence of benefit for people who have had either a mastectomy or a lumpectomy procedure, but as with any treatment, there are risks and side effects, and each person's treatment is personalized.

Read on to learn more about what a radiation boost is, the current research on it, and potential side effects.

Woman receiving radiation therapy treatments for breast cancer
Mark Kostich / Getty Images

What Is a Radiation Boost?

Radiation boosts are sometimes used in treating several types of cancer, such as cervical, brain, or rectal cancer. They also may be a part of breast cancer treatment.

The radiation boost may be given after radiation for breast cancer is complete. The focus of a boost is a little different than the previously completed treatment, though.

While the bulk of radiation therapy focuses on the whole breast, a boost targets the area of tissue where the primary tumor was located. It's meant to kill any remaining breast cancer cells in that spot that could lead to a recurrence.

However, radiation boosts aren't always a part of breast cancer treatment. Whether or not a booster dose is needed will depend on factors that include your age and the type and stage of breast cancer for which you've been treated.


The American Society for Radiation Oncology (ASTRO) recommends a booster dose for those who meet specific criteria. Primary among them is that your breast cancer cells reached to the margins, or borders, of the tissue that was removed during surgery. The radiation boost then offers an added measure of intervention to keep any of these cells from growing.

ASTRO also recommends a booster dose for:

  • Those who are age 50 and younger
  • Those between ages 51 and 70 who are diagnosed with high-grade breast cancer

It is not needed for those who:

  • Are older than 70 and have hormone receptor-positive, low or intermediate-grade breast cancer with negative margins more than 2 millimeters (mm)

Specifically for people diagnosed with ductal carcinoma in situ (DCIS), ASTRO recommends a booster dose for those who are age 50 and younger, who have high-grade DCIS, and whose cancer cells are at or within 2 millimeters of the margins.


A radiation boost includes one or more extra treatments targeted at the tumor bed, which is a small area of breast tissue where the original cancer was removed. Surgeons usually mark this area with surgical clips (made out of titanium) that remain in the body to deliver the boost to this critical area.

This targeted boost is administered using the same machine as the one used for regular treatments, but using lower amounts of radiation.


If you receive radiation treatment and a radiation boost is planned, it will be administered after your whole breast irradiation treatment sessions are complete.


A radiation boost can reduce the risk of local recurrence, especially for higher-risk individuals, although less so for those with positive margins of less than 2 millimeters.

More research is needed to further explore just how effective radiation boosts are in reducing the risk of recurrence.

Radiation Boost After Lumpectomy

Research shows that people who undergo a radiation boost have fewer local breast cancer recurrences than people who do not undergo a boost. This is especially true for people 50 or younger who are diagnosed with DCIS.

That said, even though a radiation boost significantly reduces the risk of breast cancer recurrence, it does not appear to have any effect on overall survival up to 20 years after treatment. 

Radiation Boost After Mastectomy

The same has been noted when a radiation boost has been used for people who had a mastectomy. While a radiation boost reduces local chest wall recurrence of breast cancer, this hasn't been found to translate into longer survival.

From a different angle, however, a radiation boost after mastectomy does appear to influence the success of reconstruction, with those who have a boost being more likely to have unsuccessful surgery.

What this means is that each person will need to weigh the lower risk of a chest wall recurrence against the higher risk that reconstruction won't be successful.

Side Effects

As with any treatment, side effects from a radiation boost may occur. There are short-term side effects and long-term side effects. Talk with your healthcare provider about the risks and benefits, and what you should watch for.

Short-term side effects can include:

  • Fatigue
  • Breast swelling
  • Skin redness, itching, and discoloration

Higher doses of total radiation due to the boost have been associated with a worse cosmetic outcome. Talk with your treatment team about the total radiation amount that has already been given and what the dose would be for the boost.

Long-term side effects can include:

  • Fibrosis
  • Scarring of connective tissue
  • Radiation pneumonitis
  • Rib fractures
  • Cardiac toxicity
  • Second cancers due to radiation


After radiation therapy is completed, sometimes an extra dose, or a boost, is recommended. This recommendation is based on guidelines developed based on age, margin status, and cancer grade.

Studies have shown that a radiation boost reduces breast cancer recurrence, especially for people with a DCIS diagnosis before age 50. But the boost hasn't proven to increase long-term survival. There are risks involved, so talk with your healthcare team about the benefits versus the risks, and what an added dose may mean for you.

A Word From Verywell

While receiving an extra dose of radiation may seem scary or unnecessary, you can take comfort knowing that the goal of this boost is to minimize the chances of your breast cancer returning. If your healthcare provider suggests one, but you are uncertain about moving ahead with it, have an open discussion about your concerns and ask the specific reasons behind the recommendation in your case.

Frequently Asked Questions

  • Does boost radiation mean a stronger dose?

    It's not necessarily "stronger" but adds to the total radiation therapy you receive. This is one reason for why the benefits of boost radiation need to outweigh the risks. The boost radiation dose will vary based on age, your previous treatment, specific treatment guidelines, and other factors. Ask your treatment team what dosage you might expect.

  • How many radiation boosts can I receive?

    Boost radiation means one "dose" but how you receive it may vary. The dose is divided into radiation sessions on the basis of what's called fractionation. This describes how small doses make up your total dose. Your cancer care team will choose the appropriate amount and the best schedule for your treatment.

  • Can I boost my energy during radiation therapy?

    Radiation therapy can cause fatigue, but there are ways to help conserve and even boost your energy during treatment. It's important to stay hydrated and eat a healthy diet. Although you're fatigued, limit caffeinated drinks. Exercise, even walking, has been shown to help with radiation-induced fatigue. Talk with your cancer team about whether it's safe for you to exercise during your treatment.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  4. Vrieling C, van Werkhoven E, Maingon P, et al. Prognostic factors for local control in breast cancer after long-term follow-up in the EORTC boost vs no boost trial: a randomized clinical trial. JAMA Oncol. 2017;3(1):42-48. doi:10.1001/jamaoncol.2016.3031

  5. Albert A, Mangana S, Nittala MR, Thomas TV, Weatherall L, Vijayakumar S. The impact of a postmastectomy chest wall scar boost on local recurrence-free survival in high-risk patients. Clin Breast Cancer. 2019;19(5):363-369. doi:10.1016/j.clbc.2019.04.010

  6. Naoum GE, Salama L, Ho A, et al. The impact of chest wall boost on reconstruction complications and local control in patients treated for breast cancer. Int J Radiat Oncol Biol Phys. 2019;105(1):155-164. doi:10.1016/j.ijrobp.2019.04.027

  7. Kindts I, Laenen A, Depuydt T, Weltens C. Tumour bed boost radiotherapy for women after breast-conserving surgery. Cochrane Database Syst Rev. 2017;11:CD011987. doi:10.1002/14651858.CD011987.pub2

  8. Maliko N, Stam MR, Boersma LJ, et al. Transparency in quality of radiotherapy for breast cancer in the Netherlands: a national registration of radiotherapy-parametersRadiat Oncol 2022;17:73. doi:10.1186/s13014-022-02043-0

Additional Reading
Originally written by Pam Stephan
Pam Stephan is a breast cancer survivor.
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