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Proton therapy for breast cancer

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For women and men with breast cancer, conventional treatment poses a risk to the heart and lungs as well as other nearby tissue, muscle and bone—by exposing them to radiation.


For this reason, proton radiation therapy is an increasingly common treatment for breast cancer. Compared to conventional treatment, proton therapy delivers approximately 50 percent less radiation to the lungs and almost no radiation to the heart.


As a result, patients who receive proton therapy for breast cancer are at lower risk of long-term side effects. Specifically, proton therapy reduces the risk of ischemic heart disease, a major problem caused by narrowed arteries, as well as cardiac complications, lung scarring and secondary malignancies. Also, women who receive proton therapy are typically more satisfied by the cosmetic outcome compared to traditional radiation treatment.


Recovery from proton therapy is rapid, generally with very minimal side effects.


What types of breast cancer can be treated with proton therapy?

Proton therapy can treat all forms of breast cancer. It is particularly beneficial when the cancer develops in the left breast, close to the heart. For patients whose breast cancer has spread to adjacent lymph nodes, proton therapy may treat the affected area more thoroughly.


Proton therapy can also treat any residual breast cancer that remains or recurs following breast conservation therapy or mastectomy.

Types of breast cancer treated at the New York Proton Center

The New York Proton Center treats the following breast cancers with proton therapy.

Ductal carcinoma in-situ (DCIS)

DCIS is the earliest form of breast cancer, characterized by abnormal cells confined to the milk duct of the breast. It is noninvasive, meaning it is unlikely to spread into any normal tissue beyond the milk duct.

Early (stages 1-3) invasive breast cancer

Of the four stages of invasive breast cancer, the first three are considered “early” stages:


  • Stage 1: The breast cancer is evident, but contained to the area where the first abnormal cells developed. Treatment at this stage can be highly effective.
  • Stage 2: The breast cancer is growing, but still contained to the breast and/or nearby lymph nodes.
  • Stage 3 (also “Localized Advanced Breast Cancer,” or LABC): The cancer is more advanced in the breast itself or has spread extensively to regional lymph nodes, but not to distant organs.
Inflammatory breast cancer

Inflammatory breast cancer is caused by malignant cells blocking the lymph vessels in the breast. It often spreads in a matter of months or even weeks. It is rare, accounting for under five percent of all breast cancers.


Patients with inflammatory breast cancer often do not develop a characteristic lump in the breast. Symptoms instead include:

  • breast discoloration resembling a bruise
  • pain or tenderness
  • dimpling
  • change in the appearance of the nipple
  • enlarged lymph nodes under the arm or above the collarbone.
Triple-negative breast cancer

When the three most common “receptor cells” that fuel breast cancer are not present in the tumor, the cancer is triple negative. Those receptors are:

  • estrogen receptor
  • progesterone receptor
  • human epidermal growth factor receptor 2

Conventional systemic therapies that work by blocking one or more of these receptors are often ineffective against triple negative cancer, since the receptors are not present in the first place.


For this reason, proton therapy is a highly promising alternative for treating this aggressive form of cancer.

Recurrent breast cancer

Proton therapy can benefit patients with a recurrence of their breast cancer.

Conventional treatment of a recurrence can expose the heart and lungs to harmful radiation. Proton therapy, however, delivers a highly precise and more targeted radiation dose to the tumor while minimizing the impact—and therefore any potential long-term side effects—on surrounding organs and tissues like the heart and lungs.

Pencil Beam Scanning: Highly advanced proton therapy for breast cancer

At the New York Proton Center, patients with breast cancer receive Pencil Beam Scanning. It’s the most sophisticated and precise type of proton therapy.


Pencil Beam Scanning allows clinicians to create a highly customized treatment field based on the unique shape, size and location of the breast cancer tumor—similar to traditional proton therapy, only with even greater precision.


As the name implies, Pencil Beam Scanning uses an extremely narrow beam—just a few millimeters wide—to “dot” protons onto the cancer. The process is repeated, layer by layer, like paint applied by the tip of an incredibly fine brush. The treatment is ultra-precise, capable of closely regulating the radiation dose according to the volume of the tumor.

A tailored approach to treating breast cancer with proton therapy

Most proton centers treat breast cancer with volumetric beams that deliver a fixed quantity of energy to the entire tumor and surrounding normal tissues. But the pencil beam scanning technology available at the New York Proton Center uses “intensity-modulated proton therapy,” or IMPT.


IMTP is widely considered the most advanced form of proton therapy for breast cancer. It delivers different radiation doses to different parts of the tumor based on its exact location, maximizing the chance of a cure while better protecting surrounding healthy tissue from radiation.

Latest news from NYPC
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How can we help?

Want to find out if proton therapy might be a good fit for you or your patient? Call us at 833-NYPROTON (833-697-7686) or fill out the appropriate form below.