Is intensive training with a time interval between instruction and planning CT necessary for deep inspiration breath-hold radiotherapy in breast cancer?

Background: Breathing instruction and exercises and a time gap between training and planning CT scans (pCT) is recommended as part of deep inspiration breath-hold (DIBH) assisted radiotherapy (RT). However, this is associated with additional time expenditure.

Materials and methods: In two of the authors' treatment centers (TC), patient training took place before the planning CT of DIBH-assisted therapy. In TC 1, a further appointment was made with a minimum interval of 2 days to perform the planning CT. At TC 2, the planning CT was performed immediately after the first patient instruction. A retrospective evaluation of the clinical parameters of the therapy was carried out to investigate the relevance of the time gap between DIBH exercises and pCT.

Results: A total of 72 patients were included, 35 of whom were treated in TC 1 and 37 in TC 2. In TC 1, an average interval of ~4 days was observed between patient training and planning CT, while in TC 2, training and CT were performed immediately after each other. No significant differences in radiation dose exposure of the lung on the treated side, the whole lung, or the heart were found between the two centers. Furthermore, there was no significant difference in the application of the daily RT fraction. The requirement for daily positioning checks was also the same at both treatment centers.

Conclusion: This study does not show any advantages for a time gap between instruction/training and pCT. Skipping the time break does not deteriorate any clinically relevant endpoints.