Effectiveness of oesophageal gastric junction tumour motion with and without a pneumatic abdominal compression belt in the era of precise image-guided radiation therapy

Background: To investigate the effect of a pneumatic abdominal compression belt (PACB) on suppressing the movement of primary lesions in the oesophageal gastric junction (EGJ). Materials and Methods: Titanium clips A and B were placed on the upper and lower edges of the tumour grossly in 10 patients by using gastroscopy before preoperative chemoradiotherapy. Four sets of images of clips were obtained by 4DCT in each patient with and without PACB. Nine sets of CBCT images were obtained from each patient for analysis. Paired t tests and independent t tests were used to test for differences. Results: In the cranio-caudal (CC) directions, the internal motion of clip B was smaller with PACB than without PACB (P=0.000). The interfraction motion of clip B in the left-right (LR), anterior-posterior (AP) and CC directions was smaller with than without PACB (P=0.002, 0.002 and 0.005). We determined that 0.9, 0.9 and 0.9 cm ITV margins in the LR, AP and CC directions are suggested for EGJ lesions with PACB to better cover the tumour movements. Conclusion: A pneumatic abdominal compression belt can reduce the intra- and interfraction movements of EGJ tumours during preoperative radiotherapy.