Active Breathing Coordinator in adjuvant three-dimensional conformal radiotherapy of early stage breast cancer: a...

To investigate the technical feasibility of utilizing the Active Breathing Coordinator for planning of postoperative three-dimensional conformal radiation therapy in patients with early stage breast cancer undergoing breast conservation therapy.

Patients with early stage breast cancer for whom adjuvant radiotherapy after breast-conserving surgery was planned were consecutively enrolled. Five sessions of simulation with the Active Breathing Coordinator were planned for each patient. Computed tomography for simulation was not acquired until a good level of compliance with the procedure was achieved by the patient. Patients who did not show a satisfactory level of compliance after the planned fifth session were defined as noncompliant. Two simulation computed tomography scans were acquired: the first without the Active Breathing Coordinator during free breathing, the second with the Active Breathing Coordinator. Forward intensity-modulated treatment plans were calculated. Mean lung dose (MLDipsilateral) and V30 (V30lung) for the ipsilateral lung and V30 for the heart (V30heart), were evaluated.

Twenty consecutive patients were enrolled (6 with left-sided breast cancer and 14 with right-sided breast cancer). Eighteen of the patients completed the simulation computed tomography with the Active Breathing Coordinator after 1-5 sessions (median, 3). In 16 of the 18 patients, a reduction of V301ung was observed with the Active Breathing Coordinator. In 15 of the 18 patients, a reduction of MLDipsiateral was also observed. In 5 of the 6 patients with left-sided breast cancer, a reduction of V30heart was noted.

Routine application of the Active Breathing Coordinator in clinical practice is feasible, even though it requires an increased workload. Dosimetric results are encouraging in terms of a better sparing of the ipsilateral lung and the heart.