Proton therapy to treat breast cancer

Proton therapy is currently used to treat brain, spinal and prostate cancers, as well as many paediatric tumours. Another potentially significant application is the treatment of patients with breast cancer, as proton beam therapy may offer them the benefits of radiation without some of its serious side effects, which include heart disease.

Breast cancer patients who receive radiation therapy face higher risk of heart attacks and other heart-related problems in the long run. The risk is particularly pronounced for women who receive radiation treatment for their left breast because of its position right above the heart. This is where proton therapy shows a worthy advantage, as it precisely targets cancer cells without damaging surrounding healthy tissue.

About 230,000 women are diagnosed with breast cancer in the U.S. every year. Those who receive radiation therapy fare much better on average than patients who forgo radiation, as they have lower rates of cancer recurrence. However, they also face a higher risk of secondary complications.

Indeed, patients who receive radiation therapy in the left breast have a much higher chance of having constricted blood vessels in the front of the heart, as radiation oncologists treat the cancer by aiming the beam at an angle across the chest, inadvertently exposing parts of the lung and heart to radiation. These patients are consequently at much higher risk for heart attacks and/or heart muscle damage.

Proton therapy largely sidesteps this problem by offering depth control: “It goes in a certain distance and stops. So we can treat the chest wall as the patient receives less radiation dose and we can also avoid the heart and the lungs,” Dr. William Hartsell, medical director of the CDH Proton Center.