Shanghai Chinese Clinical Medicine Press Co., Ltd.
Doi
Abstract
ObjectiveTo explore the application value of the simple foot immobilization device in radiotherapy for rectal cancer based on the inter-fractional setup error acquired by image-guided technology of cone beam computed tomography (CBCT). MethodsA total of 49 rectal cancer patients received volumetric modulated arc therapy (VMAT) in Zhongshan Hospital, Fudan University from February 2021 to February 2023 were included. Inter-fractional setup errors of each patient were analyzed. Any situation where the inter-fractional setup error exceeded 7 mm in any three-dimensional direction during the inter-fractional treatment course (the first treatment was excluded) was defined as a failed positioning reproducibility. Binary logistic regression was used for independent factor analysis of the failed positioning reproducibility. ResultsIn the X-axis, Y-axis, and Z-axis directions, the patients’ inter-fractional setup errors were (2.50±1.97) mm, (2.18±1.73) mm, and (1.17±1.06) mm, respectively. Age (OR＝0.880, 95%CI 0.801-0.967, P＝0.008) and radiotherapy mode (OR＝0.178, 95% CI 0.034-0.936, P＝0.042) were independent factors affecting failed positioning reproducibility. The area under the curve (AUC) of age predicting failed positioning reproducibility was 0.780, with an optimal cut-off value of 53.5 years old. ConclusionsThe simple foot immobilization device has good inter-fractional setup reproducibility for patients with rectal cancer who received radiotherapy, but it is not recommended for patients younger than 53.5 years with rectal cancer undergoing preoperative radiotherapy
