Tumour motion of oesophageal squamous cell carcinoma evaluated by cine MRI: associated with tumour location

AIM: To evaluate the association between oesophageal tumour motion and tumour location using cine magnetic resonance imaging (MRI). MATERIALS AND METHODS: Thirty-three consecutive patients with oesophageal squamous cell carcinoma were enrolled, and underwent cine MRI of oesophageal tumours. The maximum displacements in the anterior-posterior (A-P), superior-inferior (S-I), and left-right (L-R) directions of the tumours were assessed statistically to show their associations with tumour location. RESULTS: Tumour motion in A-P and S-I directions increased from upper to lower oesophagus (r = 0.505, p = 0.003; and r = 0.600, p<0.001, respectively). In A-P and S-I directions, tumours showed larger motion in the lower oesophagus than in the upper or middle oesophagus (all p< 0.05). Motion of middle and lower oesophageal tumours in the S-I direction was larger than in L-R or A-P direction (all p< 0.05). To provide 95% geometric coverage for the motion of upper oesophageal tumours, statistical analysis showed margins of 3.75 mm in L-R direction, 3.72 mm in A-P direction, and 5.38 mm in S-I direction. For the motion of tumours of the middle oesophagus, 95% coverage required margins of 8.50, 6.62, and 11.96 mm in L-R, A-P, and S-I directions, respectively, and for lower oesophageal tumours, 95% coverage required margins of 9.17, 9.68, and 12.98 mm in L-R, A-P, and S-I direction, respectively. CONCLUSION: Oesophageal tumour motion in different directions can be associated with tumour location as shown on cine MRI, suggesting that the present findings could be helpful for better understanding oesophageal tumour motion and gating individualised radiation delivery strategies. (C) 2018 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.