Rationale:

The number of breast cancer (BC) patients at risk for long-term radiation-induced health problems is increasing, as their outcome is improving due to intensified treatment regimens, such as new systemic approaches and radiotherapy. Therefore, identifying BC survivors with the highest risk for radiation-induced health problems is crucial for developing strategies for primary and secondary prevention, which may contribute to healthy ageing.

Inclusion Criteria:

• Female gender.
• Treated for stage I-III invasive adenocarcinoma of the breast or ductal carcinoma in situ (DCIS).
• Treated with curative breast-conserving surgery followed by radiotherapy of the breast, with or without irradiation of the regional lymph nodes.
• Start of radiotherapy is between 01-01-2005 and 31-12-2008.
• Available planning CT scan and dose distribution data of original breast cancer irradiation.

Exclusion Criteria:

• Any prior malignancy other than non-melanoma skin cancer or breast cancer.
• Prior radiotherapy treatments in the thoracic region.
• Treated with neoadjuvant chemotherapy.

Adult, female patients with stage I-III breast cancer, who were treated with breast-sparing surgery followed by radiation treatment.