Effect of end expiration breath hold on target volumes and organ at risk doses for oesophageal cancer radiotherapy

Abstract

Background and Purpose

The end expiration breath hold (EEBH) technique has the potential to reduce tumour motion during radiotherapy treatment of lower oesophageal cancer, and therefore, motion artefacts, target volumes and dose to surrounding organs at risk (OAR). EEBH is an emerging technique and clinical data on its use in oesophageal cancer is scarce.

Methods and Materials

A comparison of 20 lower oesophageal cancer patients was performed for radiotherapy treatment plans in both EEBH and free breathing (FB). EEBH and FB plans were evaluated and compared in terms of motion artefacts, target volumes and dose-volume metrics.

Results

EEBH was effective in reducing the observed motion artefacts seen in planning CTs compared to FB. EEBH also significantly reduced the average PTV size between EEBH and FB (ΔV = -48 ± 55 cm³; p < 0.001). OAR-PTV overlap volumes were also effectively reduced in EEBH compared to FB, including for lung-PTV overlaps (ΔV = -13 ± 13 cm³; p < 0.001) and for heart-PTV overlaps (ΔV = -8 ± 14 cm³; p = 0.02). Mean heart doses were lower on average by −1.2 ± 2.0 Gy with EEBH (p = 0.02), and mean lung doses by −1.0 ± 1.0 Gy (p < 0.001). Mean liver doses were on average reduced with EEBH by −0.6 ± 1.5 Gy, whereas spinal D_2cm3 increased in EEBH compared to FB by 1.8 ± 6.3 Gy, but neither were statistically significant.

Conclusion

Use of EEBH for oesophageal cancer radiotherapy reduced motion artefacts and increased confidence in contouring volumes. Additionally, planning target volumes and doses to key OARs were reduced with EEBH compared to FB plans.