Proton Therapy for Breast Cancer

Scripps Health in San Diego offers proton therapy for the treatment of breast cancer.

Targeted Radiation Therapy for Breast Cancer

Scripps Health cares for more breast cancer patients than any other San Diego health care provider. Depending on the stage, breast cancer may require surgery, chemotherapy, radiation, or a combination of these treatments.

Proton therapy is a highly precise form of cancer radiation treatment that enables us to target tumors within intricate areas while sparing healthy surrounding tissue.

Breast Cancer Treatment

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Why Choose Scripps


From diagnosis and treatment to navigation and support, Scripps offers comprehensive cancer care. Learn how proton therapy further complements these services.

About Proton Therapy


Proton Therapy Expertise

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The clinical and scientific teams have more than 90 years of combined experience treating patients with proton therapy. Learn more about the experts at the center.

Radiation therapy for the treatment of breast cancer

Ideally, radiation treatment for breast cancer will:

  • Target the tumor only
  • Protect your heart, lungs and spinal cord
  • Maintain your quality of life during treatment
  • Reduce side effects of radiation therapy

Radiation used to treat breast cancer must be delivered with high precision and the utmost care to maximize the dosage to cancerous cells and minimize harmful exposure beyond the tumor. This is especially important for breast cancer patients, who may face the risk of secondary cancers, lung injuries and major cardiac events later in life due to previous radiation exposure.

Radiation therapy used to treat breast cancer must be precise because:

  • Radiation to healthy tissues around breast tumors can affect the heart, lungs and spinal cord. These structures are very sensitive to radiation even at low dosages, and damage to them can have significant side effects. This is especially true with tumors located in the left breast. Given the proximity to the heart, there is an increased risk of the heart receiving radiation.
  • Breast cancer that has spread to the lymph nodes may require radiation even after surgery, and the radiation field may extend to the chest wall, underarm area, collarbone and sternum. When lymph nodes are included in the radiation field, the risk to the heart and lungs is higher.
  • As breast cancer survival rates continue to increase, so do concerns about the long-term side effects of radiation exposure. In many cases, long-term effects may have a far greater impact on quality of life than the original cancer.
  • If cancer comes back after radiation therapy, treatment options may be limited. A second round of radiation treatment is often not possible due to the high risk of injury to these vital organs and tissues.

Proton therapy for breast cancer

With any radiation technique, the potential for serious complications can be high in some cases. This can lead to a difficult choice between giving:

  1. a less-than-optimal dose into the breast tumor (which reduces the chance of remission); or
  2. an ideal dose to the tumor with a higher risk of radiation to healthy tissues.

Protons deposit their maximum energy directly into the tumor, so exposure to your heart, lungs, bone and healthy tissue is greatly reduced.

  • Intensity-Modulated Proton Therapy (IMPT), available in California only at the Scripps Proton Therapy Center, allows doctors to more selectively place high-dose radiation in your tumor, while simultaneously reducing the dose to your surrounding critical organs. This can lower the risk of side effects from the radiation treatment.
  • A test of treatment plans for women with left-sided breast cancer undergoing breast-conserving therapy (X-ray vs. intensity-modulated protons) found that:
    • Radiation dose to the lung was reduced by 81 percent
    • Radiation to the other breast was reduced by 96 percent
    • Radiation dose to the heart was reduced by 99 percent
  • Combined treatments of mastectomy or lumpectomy surgery, chemotherapy and radiation may be needed for some breast tumors. Proton therapy reduces the radiation-related toxicity, which increases the likelihood that patients can complete treatment with fewer interruptions or delays.
  • When compared with conventional passively scattered protons, Scripps Proton Therapy Center’s intensity-modulated pencil-beam scanning technique (IMPT) can treat more complex tumor shapes, vary the dosage within the tumor and reduce the amount of radiation to surrounding tissues. The radiation dose from pencil-beam scanning that extends beyond the target tumor has been shown to be substantially less than passively scattered protons and intensity-modulated X-ray therapy (IMRT).

Scripps Proton Therapy Center provides advanced radiation treatments for breast cancers including:

  • Early stage breast cancer
  • Locally advanced breast cancer (Stage II and III)
  • Ductal carcinoma in-situ
  • Triple-negative breast cancer

Proton therapy for recurring cancer

Proton therapy is often the best way to treat recurring tumors in areas that have previously been treated with radiation therapy.

Treating previously irradiated areas is challenging and very risky. The healthy tissues around the recurrent tumor do not “forget” the previous radiation dose, and any added dose continues to increase the risk of normal tissue injury. Proton therapy enables doctors to better concentrate the dose to the target and limit it elsewhere, allowing re-treatment with radiation in selected patients.

See the evidence supporting proton therapy as a treatment for breast cancer.

Support services for breast cancer

When you are living with breast cancer, you may need more than expert medical treatment. Our cancer specialists are here to help you and your family every step of the way, from scheduling appointments and answering questions to finding support services and other resources.

We offer a wide variety of services to help speed your recovery, including:

Learn more about our cancer support services and resources.

Proton therapy is a highly precise form of external radiation therapy that can be used for tumor control in select patients. All cancer treatments have advantages and disadvantages. Be sure to discuss these, as well as your treatment options, with your cancer specialist.

Evidence supporting proton therapy for breast cancer