Radiation therapy should ideally start 6-8 weeks after breast-conserving surgery but no later than 12 weeks after the surgery.
If adjuvant chemotherapy has been administered, it is recommended to start radiation therapy three weeks after chemotherapy (optionally, it can be completed before beginning chemotherapy).
The radiation therapy procedure follows the existing clinical protocol for breast radiotherapy. For radiation therapy planning, the patient is positioned supine using immobilization devices (such as a wing board or similar) to ensure daily reproducibility within a range of 5 mm. The clinical target volume (CTV) is delineated according to the recommendations of the Danish Breast Cancer Cooperative Group (DBCG) and the European Society for Radiotherapy and Oncology (ESTRO).
A total dose of 26Gy in 5 fractions every working day using the Volumetric Modulated Arc Therapy (VMAT) technique. Daily portal images are obtained, and a breathing control protocol is applied based on clinical assessment.
