Safe, Effective Breast Cancer Treatment Protects Heart, Lung Tissues from Harm
While radiation therapy is an essential part of breast cancer treatment for many women, the heart and lungs are unavoidably exposed to low doses of radiation therapy in the process. At least one major study has demonstrated the correlation between increased doses of radiation to the heart and cardiac side effects. 
However, multiple studies have demonstrated that proton therapy reduces radiation exposure to the heart and lungs [2-4]. Early clinical trials have also shown that proton treatment is safe and effective. [5-8]
Factors that influence the decision to treat breast cancer with proton therapy include:
- Patients with left-sided tumors may benefit more because proton therapy has been shown to decrease the dose to the heart compared to conventional photon therapy, especially when patients are receiving treatment to their regional lymph nodes. [2-4]
- Proton therapy allows more dose to be delivered to the areas at risk, especially the internal mammary lymph nodes (IMN), while reducing the dose to the lungs and heart.[5-7]
- Facing a longer life-span, young patients may benefit more from proton treatment because of its decreased radiation dose, toxicity and long-term side-effects, including recurrent cancers, heart and lung disease.
1. Darby SC et al., Risk of ischemic heart disease in women after radiotherapy for breast cancer. N Engl J Med. 2013 Mar 14;368(11):987-98.
2. Lin et. al, Proton beam versus photon beam dose to the heart and left anterior descending artery for left-sided breast cancer. Acta Oncologica, 2015 Jul;54(7):1032-9.
3. MacDonald et al., Proton radiotherapy for chest wall and regional lymphatic radiation; dose comparisons and treatment delivery. Radiation Oncology, 2013;8:71.
4. Wang et al., External-Beam Accelerated Partial Breast Irradiation Using Multiple Proton Beam Configurations. International Journal of Radiation Oncology • Biology • Physics, 2011, Volume 80, Issue 5, 1464-1472.
5. MacDonald et al., Proton Therapy for Breast Cancer After Mastectomy: Early Outcomes of a Prospective Clinical Trial. International Journal of Radiation Oncology • Biology • Physics, 2013, Volume 86, Issue 3, 484-490.
6. Cuaron, John J. et al. Early Toxicity in Patients Treated with Postoperative Proton Therapy for Locally Advanced Breast Cancer. International Journal of Radiation Oncology • Biology • Physics, Volume 92, Issue 2, 284 – 291.
7. Bradley, Julie A. et al. Initial Report of a Prospective Dosimetric and Clinical Feasibility Trial Demonstrates the Potential of Protons to Increase the Therapeutic Ratio in Breast Cancer Compared with Photons. International Journal of Radiation Oncology • Biology • Physics, Volume 95, Issue 1, 411 – 421.
8. Verma et al., Proton beam radiotherapy as part of comprehensive regional nodal irradiation for locally advanced breast cancer. Radiotherapy & Oncology. May 2017; Vol 123(2): 294-298.