Proton therapy for breast cancer

Proton therapy, also known as proton beam therapy, is a unique type of radiation therapy that uses high doses of radiation to kill cancer cells. Proton therapy helps treat breast cancer because it can target tumors more precisely than conventional radiation. It also minimizes damage to critical surrounding organs such as the heart and lungs.

This article will describe what proton therapy is and its benefits for breast cancer patients.

What is proton therapy?

Proton therapy uses charged particles called protons to target and kill cancer cells. Proton therapy is also known as proton radiation therapy, proton beam therapy, or intensity-modulated proton therapy (IMPT). Proton therapy helps treat tumors close to vital organs or areas of the body.

External beam radiation (radiation directed at the cancer) is the most common type of radiation therapy for breast cancer. Proton therapy is a special external beam of radiation that is less likely to harm surrounding healthy tissue because it targets only the tumor in a focused manner.

Why do you get breast cancer?

Breast cancer is a cancer that starts in the breast tissue. Breast cancer cells often form a tumor that can be seen or felt as a lump on X-rays. The breasts are close to the heart and lungs, and radiation can cause damage to these vital organs. Proton beam therapy can help treat breast cancer while reducing the risk of radiation damage.

Radiation Enhancement May Reduce Risk of Breast Cancer Recurrence

What is proton therapy for breast cancer?

Proton therapy is a precise form of radiation therapy that allows your medical team to better target cancer cells than traditional X-ray radiation therapy. If your tumor is large, you had a mastectomy, or the cancer has spread to nearby lymph nodes, your healthcare team may consider proton therapy as part of your breast cancer treatment plan.

Proton therapy can be used for breast cancer that has not spread beyond the breast area. Metastatic cancer — cancer that has spread to distant parts of the body — is not eligible for proton therapy. This is because proton therapy tightly targets cancerous tumors and cannot be used throughout the body (whole body).

How does proton therapy work?

Proton therapy destroys cancer cells by using radiation to damage the DNA in them.

During the appointment, your radiographer will use Synchrotron Machines accelerate protons. Accelerating the protons increases their energy and pushes them through nozzles on the machine. The protons can then travel to a set depth in the body and release a high dose of radiation. Because the depth can be specified, these protons do not extend beyond the tumor.

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Proton Therapy vs Standard Radiation

There are many similarities between proton therapy and traditional X-ray therapy. They both attack and kill cancer cells by damaging the DNA inside the cells. Proton therapy and X-ray radiation therapy usually require the same number of visits.

Conventional X-ray radiation delivers beams of photons that can reach both the tumor and tissues outside the tumor. When photons damage healthy cells around a tumor, serious side effects can occur.

The protons used in proton therapy have unique properties that healthcare providers can use to deliver radiation to specific depths in the body. When proton therapy is given, all the energy is released as it reaches the tumor site. Because there is no radiation dose beyond the tumor, proton therapy has fewer side effects and complications.

Studies have shown that patients receiving proton therapy are much less likely to experience serious side effects than those receiving X-ray radiation. Patients who received proton therapy were also more likely to continue their daily activities. Both types of radiation appear to have the same level of efficacy on cancer cells.

It’s important to note that proton therapy is more expensive than traditional radiation therapy, and not all insurance policies cover it.


Proton therapy is more precise than traditional radiation therapy. This means it is better able to target cancerous tumors without damaging surrounding tissues and organs.

How does radiation therapy work and is it right for me?

How Proton Therapy Helps Treat Breast Cancer

Proton therapy has been found to be effective in treating breast cancer. Because the breasts are so close to vital organs like the heart and lungs, proton therapy can treat cancerous tumors without destroying these vital structures.

The benefits of proton therapy for breast cancer

There are several potential benefits of using proton therapy to treat breast cancer. The proton beam used in proton therapy does not reach tissues other than the cancerous tumor. This reduces the risk of normal tissue damage and reduces side effects. This is especially helpful for people with left-sided breast cancer because the tumor is very close to the heart.

Proton therapy also uses higher doses of radiation, giving it a better chance of destroying tumors. Possible benefits of using proton therapy for breast cancer include:

  • Fewer side effects than traditional treatments
  • Reduce the risk of heart and lung damage
  • Painless
  • Can be used with other treatments such as chemotherapy

Overview of Cancer Treatment

Types of Breast Cancer Proton Therapy Can Treat

Proton therapy can be used for breast cancer that has not spread to distant areas of the body. Once breast cancer has metastasized to other organs, proton therapy is likely to be ineffective. This means that patients with stage 1, 2 or 3 breast cancer may benefit from proton therapy.

Locally advanced breast cancer is also a candidate for proton therapy. This means that the cancer has spread but has been stuck in the same area of ​​the breast. This includes cancer cells in areas such as the chest wall, chest skin, or lymph nodes under the arm.

The following types of breast cancer may benefit from proton therapy:

  • Ductal carcinoma in situ
  • inflammatory breast cancer
  • invasive ductal carcinoma
  • invasive lobular carcinoma
  • triple negative breast cancer
  • triple positive breast cancer
  • Estrogen receptor positive or negative
  • Progesterone receptor positive or negative
  • HER2/neu positive or negative

Proton Therapy: What to Expect

The first step in delivering proton therapy is meeting with your oncology team. Your team will discuss your treatment options and make recommendations based on your breast cancer stage and overall health.

Once you decide to go ahead with proton therapy, your medical team will determine exactly where your tumor is in your breast. This is done through a mapping process using magnetic resonance imaging (MRI) or computed tomography (CT). This appointment is called a mock appointment. Once your medical team has created a 3D map of your tumor, they will use a computer program to calculate your radiation dose and where to give it.

During your proton therapy appointment, you will go to a private treatment room and receive radiation therapy on a dedicated treatment table. Your medical team may place an immobilization device to keep your body in the same position. The entire appointment usually takes about 30 minutes. Most treatment options consist of five appointments per week for several weeks.


Proton therapy appointments usually last 30 minutes. Patients undergoing proton therapy can expect to attend five appointments per week for several weeks.

Proton Therapy Side Effects

While proton therapy appears to cause far fewer side effects than conventional radiation therapy, side effects and complications can still occur. Radiation of any type must first pass through the skin, so skin changes are common. Possible side effects of proton therapy include:

  • redness of the skin (similar to a sunburn)
  • dry and irritated skin
  • blister
  • swelling
  • fatigue
  • Temporary hair loss on site

Long-Term Effects of Radiation Therapy Everyone Should Know


Proton therapy is a unique type of radiation therapy that targets tumors and delivers high doses of radiation to kill cancer cells. Proton therapy is able to target cancer cells without causing significant damage to surrounding tissues and organs. This is especially important for people with breast cancer because their tumors are close to vital organs such as the heart and lungs.

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Going through the breast cancer diagnosis and treatment process can be overwhelming and can be one of the most stressful times of your life. It can be helpful to know that there are always new treatments being developed to treat breast cancer better with fewer side effects. Discuss proton therapy with your healthcare provider and ask if your type of cancer qualifies for this treatment.

Frequently Asked Questions

  • What is the success rate of proton therapy for breast cancer?

    Proton therapy is a very successful treatment option. A 2019 study of patients who received proton therapy after mastectomy (surgical removal of the breast) found that participants had a three-year survival rate of 97.2 percent.

  • Is proton therapy better than other treatments?

    Proton therapy may be effective in treating breast cancer. Patients with stage 1, 2, or 3 breast cancer may be candidates for proton therapy.

  • How long does proton therapy take for breast cancer?

    Proton therapy for breast cancer is usually given five times a week for several weeks.

  • Is proton therapy better than chemotherapy?

    Proton therapy is a different treatment than chemotherapy, and the two can be used together. Chemotherapy attacks and kills cancer cells as well as healthy cells in the body. Proton therapy can directly target cancerous tumors without damaging surrounding tissue.