2099 - Efficacy and Safety of Thermoplastic Film Thermostatic Heating in Radiotherapy for Upper Abdominal Tumors: A Prospective Randomized Controlled Trial
Presenter(s)
Q. X. Hu1, F. Zhang2, L. Zixuan3, J. Li4, L. Bo5, L. Zhang6, W. X. Yao7, L. L. Xu1, L. Zhao8, and F. Bai9; 1Department of Radiation Oncology,Xijing Hospital,Air Force Medical University CN, xi'an, ShaanXi, China, 2State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers and Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, Xi’an, China, China, 3Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University. Xi’an, China, Xi'an, Shaanxi Province, China, 4Department of Radiation Oncology,Xijing Hospital,Air Force Medical University CN, Xi’an, China, 5Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University. Xi’an, China, Xi'an, Shanxi, China, 6Department of Radiation Oncology,Xijing Hospital,Air Force Medical University CN, Xi'an, ShaanXi, China, 7Xijing Hospital, First Affiliated Hospital of Air Force Medical University, Xi’an, Shaanxi, China, 8StateKey Laboratory of Holisticntegrative Managementof Gastrointestinal Cancersand Department of RadiationOncology,Xijing Hospital,Fourth Military MedicalUniversity, Xi'an, China, 9Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, xi'an, Shaanxi, China
Purpose/Objective(s): Thermoplastic film is the conventional fixation method for radiotherapy in patients with upper abdominal tumors. However, since thermoplastic films are typically stored in treatment rooms at ambient temperature (approximately 24°C), patients often experience poor somatosensory comfort during fixation, which may lead to involuntary movement. To address this issue, we propose preheating the thermoplastic film prior to radiotherapy to enhance positioning accuracy and patient comfort.
Materials/Methods: This prospective study enrolled patients with upper abdominal tumors who underwent radiotherapy at our department from June 2023 to December 2024. Patients were randomly allocated into two groups using a numerical table method. The experimental group preheated the thermoplastic film for 10 minutes using a 37°C thermostat, and then the patients were given position fixation and treated, while the control group underwent standard fixation without preheating. Cone-beam computed tomography (CBCT) scans were performed weekly to record setup errors in the X, Y, and Z directions, as well as rotational (Rtn) errors. The CTV to PTV margin were calculated using 2.5?+0.7?. Patient comfort was assessed using a modified Likert questionnaire, which included eight items scored on a 1-5 scale. Comfort surveys were conducted after simulated positioning and on the sixth treatment session. Skin toxicity was evaluated using the CTCAE V3.0 criteria before and weekly during treatment.
Results: Of the 126 patients initially enrolled, 121 (59 in the experimental group and 62 in the control group) were included in the final analysis, with a median age of 57 years (range: 25-83 years) and a male-to-female ratio of 81:30. The median setup errors in the X, Y, Z directions and bed angle for the experimental group were 1 (0, 2) mm, 2 (1, 4) mm, 1 (1, 2) mm, and 0.6 (0.1, 1.1)°, respectively, compared to 1 (1, 2) mm, 2 (1, 3) mm, 2 (1, 3) mm, and 0.6 (0.1, 1.1)° in the control group. A statistically significant difference was observed in the X-axis direction (Z = -2.019, P = 0.044), but not in the Y, Z directions or bed angle. The PTV margins in the X, Y, and Z directions for the experimental group were 3.848 mm, 3.848 mm, and 4.448 mm, respectively, compared to 3.995 mm, 5.563 mm, and 5.033 mm in the control group, indicating smaller overall margins in the experimental group. Comfort scores after simulated positioning were 30.18 ± 3.09 vs. 30.29 ± 3.01 (P = 0.48), and after the sixth treatment session, they were 33.125 ± 4.81 vs. 30.26 ± 3.15 (P < 0.01). No grade 2 or higher skin toxicities were reported; grade 1 skin toxicity occurred in 2 patients in the experimental group and 1 patient in the control group (P > 0.05).
Conclusion: Preheating thermoplastic films before radiotherapy significantly improves patient comfort and reduces setup errors in the X direction, as well as PTV margins in the Y and Z directions. This approach is safe and effective for enhancing the precision and tolerability of radiotherapy in patients with upper abdominal tumors.