A left-sided breast cancer patient considers proton therapy while looking at imaging scans with doctor

Proton Therapy For Left-Sided Breast Cancer: Why Choose This Treatment?


Breast cancer is the most commonly diagnosed cancer for females, with one in eight being diagnosed in her lifetime. The National Breast Cancer Foundation, Inc. says that, on average, a woman is diagnosed with the disease every 2 minutes in the United States. As the second leading cause of death for women, breast cancer takes the lives of more than 40,000 American women each year.

Treatments for breast cancer include chemotherapy, hormone therapy, targeted therapy, surgery, and radiation. As there is not one perfect formula to eliminate the disease, many patients will need to undergo a combination of these treatment methods.

However, in some cases certain treatments pose higher risks. For women with left-sided breast cancer, it is important to consider what type of radiation is best. Since the tumor is close to the heart, certain treatments can cause significant damage to this vital organ, while other treatments may avoid unnecessary radiation exposure.

In these cases, proton therapy is often a better option.

What Is Traditional Radiation?

Oncologists have been using radiation therapy since the beginning of the 20th century, making it one of the most dependable cancer treatments to date. This method, along with chemotherapy and surgical procedures, are frequently prescribed for a wide variety of cancers.

According to the American Cancer Society, radiation therapy “uses high-energy particles or waves, such as x-rays, gamma rays, electron beams, or protons, to destroy or damage cancer cells.” Again, this treatment is either used alone or in combination with other drugs to shrink and destroy the cancerous area.

Patients generally receive radiation therapy in one of three forms: external radiation (with a machine), internal radiation (through an implant), and systemic radiation (through an IV or by mouth).

Traditional Radiation May Not Be The Best Option For All Breast Cancer Patients

Traditional x-ray radiation/IMRT (Intensity-Modulated Radiation Therapy) uses computer controlled linear accelerators to deliver radiation doses to a malignant tumor.

Women who are undergoing radiation treatment for breast cancer, especially of the left breast, may face higher risk for health complications down the line. This is because the x-ray beams are targeted at a body region shared with the heart and other vital organs. Traditional radiation is often criticised for this reason, as it may destroy the cancer cells, but also destroy healthy cells in the process. According to a study published in the New England Journal of Medicine, if these healthy cells are located in the heart, the patient could experience serious health issues in the future .

New research published in JAMA Internal Medicine quantifies this risk. According to the study, women who have received radiation treatment for breast cancer face a 0.5-3.5% higher risk of heart attack or other cardiovascular conditions. The researchers also said in the study that this risk is higher for women who have been treated for left-sided breast cancer because of the radiation target’s proximity to the heart.

These harmful effects may not show up right away either. The European study published in The New England Journal of Medicine found that these harmful cardiovascular effects generally appear as soon as five years after treatment. This means that the patients who have undergone radiation may feel healthy for several years before experiencing these heart issues.

Proton Therapy Is A Viable Solution To Avoid Cardiovascular Harm

Proton therapy could help patients avoid these adverse effects, targeting the cancer cells in the breast tissue, while avoiding the healthy cells of the heart, lungs, and other organs. If the treatment is successful, the patient can experience a healthy, cancer-free life without anticipating cardiovascular issues later on.

This treatment is a form of radiation, as it still uses high-energy beams to target problematic areas of the body. The difference? Proton therapy is more targeted. The protons send their full energy directly into the tumor site, reducing radiation exposure to the heart, lungs, bone, and other healthy tissue.

According to The National Association of Proton Therapy, this treatment is non-invasive and painless for the patient. Because of its highly-targeted nature, proton therapy has minimal side effects. Much like traditional radiation therapy, proton therapy can also be used in conjunction with other treatments and drugs, making it customizable to each patient’s specific needs.

Oncologists will prescribe proton therapy for anywhere from one day to eight weeks, depending on the location, size, and severity of the cancer. According to the NAPT, this treatment is often chosen for children to protect their growing bodies from the adverse effects of x-ray radiation.

Proton therapy is not an oncology treatment newcomer. It began as a cancer treatment over 50 years ago and has been used in a hospital setting since 1990. Scientists have been enhancing the treatment over the past several decades years, using technology, imaging, and computer software to deliver protons more accurately and to target breast cancer specifically.

Proton Therapy’s Proven Benefits For Breast Cancer Patients

Recent studies have shown the direct benefit of proton therapy for breast cancer. Since this therapy directly targets the breast tissue, avoiding surrounding organs, researchers have found that survival rates are increasing and adverse health effects are decreasing.

In a 2014 clinical trial by Loma Linda University in California, researchers monitored 100 breast cancer patients who underwent proton therapy treatment. The study tracked the patient’s health for the five years following the end of treatment, and found “the in-breast recurrence-free survival rate was as high as 97% with minimal effects to the breast, lungs, and heart.”

David Bush, M.D., Vice-Chairman of the Department of Radiation at the Loma Linda and one of the main researchers on the study, said in a press release that these results show great potential for the future of breast cancer treatments.

“With proton therapy the size of the radiation area is reduced significantly, lessening radiation exposure to the heart, lungs, and other parts of the body,” Bush said. “Proton beam allows us to do this better than any other type of radiation treatment.”

The researchers also found that proton therapy reduced the average breast cancer treatment time from seven to two weeks. Patients also showed that the treatment preserves the outer appearance of the breast, with 90% of patients and physicians rating the appearance of the skin as “good” or “excellent” during the five years following treatment. The researchers cited past studies that have shown that this cosmetic preservation diminishes over time and were ultimately optimistic about their results.

“This study confirms that proton therapy effectively eradicates tumors while also preserving the cosmetic appearance of the breast,” Bush said. “Clearly this is very good news for breast cancer patients.”

Proton Therapy Boosts Vitality For Breast Cancer Survivors

There are over 3.8 million breast cancer survivors alive in the United States today, according to the National Breast Cancer Foundation, Inc. With access to better treatments, survivors can live a life free of health complications from their cancer treatment. Otherwise, these individuals are forced to move forward not knowing whether organs and tissues were damaged by radiation, leaving them anticipating other problems.

Proton therapy may be the solution to this fear.

By targeting only the cancerous cells and tumors, the protons only damage and shrink the cells they are meant to affect. This means that harm to surrounding organs and tissues is greatly reduced, diminishing the risk of diseases and complications once the patient has entered remission.

For left-sided breast cancer patients, this could be the key to a healthier life after treatment. With traditional radiation therapies risking damage to the heart, lungs, bones, and other tissue, patients could unknowingly walk away from their last treatment session with harm to their bodies. Proton therapy takes away this guessing game.

Knowing the proven benefits of proton therapy for breast cancer and other types of cancers, industry leaders are opening facilities all over the United States. As more proton therapy centers open, more breast cancer patients will have access to this form of treatment. These facilities will also offer more opportunities to collect data and perform research on the effectiveness of this treatment, laying the foundation for more scientific advancement. If oncologists have access to more facilities and better technology, we will likely see more healthy cancer survivors.