The purpose of this study is to determine whether a new technique of radiotherapy for breast cancer (helical tomotherapy) can induce cardiac toxicity that would be detected in the first two years after treatment. Screening of subclinical cardiac lesions with non-invasive cardiac imaging techniques combined with measures of circulating biomarkers of cardiac tissue lesions and coronary lesions would allow assessing radiation-induced cardiac toxicity at an early stage.

REBECCA study will consist in a monocentric prospective cohort that will include 120 women volunteers treated with adjuvant tomotherapy for breast cancer in the Institut Regaud Claudius-Toulouse (ICR) and followed for 2 years after radiotherapy.

In summary, women aged between 40 and 70 years, surgically treated at ICR for breast cancer and for whom adjuvant radiotherapy with tomotherapy is indicated, with no indication of chemotherapy will be eligible for the study.

Inclusion Criteria:

• Women treated surgically for left or right breast cancer and for who adjuvant treatment is radiotherapy with irradiation of the breast or chest wall irradiation and possibly lymph node chains,
• Age between 40 and 70 years
• Adjuvant Radiotherapy is helical tomotherapy performed at Institut Claudius Regaud(Toulouse, France)

Exclusion Criteria:

• Indication of adjuvant chemotherapy
• Clinically or radiologically detectable metastasis
• Personal history of coronary artery or myocardial disease
• Personal history of breast cancer or other cancer requiring radiotherapy to the chest
• Contraindications to injection of iodinated contrast ( for CT ) : pregnancy , renal failure, allergy.
• Pregnancy, lactation
• Before radiotherapy, LVEF <50%
• Before radiotherapy, longitudinal strain > - 16 %
• Before radiotherapy,longitudinal strain rate <1% / s
• Before radiotherapy, segmental wall motion abnormality
• Coronary CT before radiotherapy showing that a therapeutic treatment is required