Proton Therapy for Primary Breast Cancer

Area of Science:

• Medical physics
• Radiation oncology
• Cardiology

Background:

• Photon-based radiotherapy (RT) for left-sided breast cancer poses a risk of cardiac complications due to radiation dose to the heart.
• The risk is linked to the mean heart dose and specific doses to coronary arteries.
• Proton therapy's Bragg peak physical property allows for precise dose deposition, potentially sparing surrounding normal tissues.

Purpose of the Study:

• To evaluate the dosimetric advantages of proton therapy over photon-based RT for left-sided breast cancer.
• To assess the potential of proton therapy in reducing cardiac dose and associated complications.
• To review early clinical tolerance and ongoing research into proton therapy for breast cancer.

Main Methods:

• Dosimetric comparison analysis between proton therapy and photon-based RT.
• Evaluation of target coverage (chest wall ± breast plus draining lymphatics) and organ-at-risk sparing (heart, coronary arteries).
• Review of early clinical data and ongoing prospective clinical trials.

Main Results:

• Proton therapy demonstrates dosimetric advantages in sparing the heart, especially with increasing target complexity.
• Uncompromised target coverage is achievable with proton therapy.
• Early clinical data suggest good tolerance to proton therapy without unexpected complications.

Conclusions:

• Proton therapy is a promising alternative to photon-based RT for left-sided breast cancer, offering superior heart sparing.
• Further prospective clinical trials are necessary to confirm the clinical benefit and identify optimal patient subgroups.
• Proton therapy may reduce long-term cardiac risks in breast cancer patients.