Mulla Zaheeda, Hashem Rania, AlMohamad Abdullah, Weber Amina, Habibullah Hanadi, Abdulmoula Ghassan, Mohiuddin Mohamed G, Ujaimi Reem
Department of Oncology, King Faisal Specialist Hospital and Research Center-Jeddah, Jeddah, Saudi Arabia.
Department of Radiology, King Abdul-Aziz University Hospital, Jeddah, Saudi Arabia.
Adv Radiat Oncol. 2022 Oct 25;8(1):101108. doi: 10.1016/j.adro.2022.101108. eCollection 2023 Jan-Feb.
This study aimed to analyze the effect of body mass factors (BMFs) on setup errors in gynecologic tumors, and whether the planned tumor volumes (PTVs) are adequate for obese patients.
This was a retrospective study of 46 consecutive female patients with gynecologic tumors who were treated with volumetric modulated arc therapy. Setup accuracy was verified using daily cone beam computed tomography. Accuracy was determined for each fraction by testing 2 different PTVs (cutoff I = ≤0.7 cm; cutoff II = ≤1.0 cm). A pooled analysis was conducted to test the association between accuracy levels (within vs beyond PTV) and the mean and variance of body mass index (BMI), umbilical (UC), and hip circumference (HC). A receiver operating characteristics curve analysis was carried out to test the sensitivity of BMI, UC, and HC in predicting inaccurate setup.
A significant association between BMFs and level of accuracy was observed in the lateral and vertical directions, but not in the longitudinal direction. In the lateral direction, inaccurate setups were associated with a greater BMI (mean difference: ∼3.50 kg/m; = .001), UC (∼10 cm), and HC (∼8 cm) compared with accurate setups ( < .001). With respect to the vertical direction, inaccurate setups (>0.7 cm margin [cutoff I]) were associated with a greater BMI (mean difference = 7.4 kg/m; = .001), UC (5.3 cm; < .001), and HC (16.0 cm; < .001) with reference to accurate setups. The receiver operating characteristics curve analysis showed that a BMI >31.4 kg/m was predictive for inaccurate setup in the vertical direction with 90.0% sensitivity with respect to cutoff I. Furthermore, a BMI >30.3 kg/m was predictive for inaccurate setup in the lateral direction with 92.5% sensitivity with respect to cutoff II.
The accuracy of radiation therapy setups for gynecologic tumors is highly sensitive to patients' BMI, notably in the lateral and vertical directions. We suggest that daily cone beam computed tomography should be applied on patients with a BMI >30.3 kg/m, using customized protocols that are lower in dose and comparable in image quality.
本研究旨在分析体重因素（BMFs）对妇科肿瘤摆位误差的影响，以及计划靶体积（PTV）对肥胖患者是否足够。
这是一项对46例接受容积调强弧形放疗的连续妇科肿瘤女性患者的回顾性研究。使用每日锥形束计算机断层扫描验证摆位精度。通过测试2个不同的PTV（截断值I =≤0.7 cm；截断值II =≤1.0 cm）来确定每个分次的精度。进行汇总分析以检验精度水平（PTV内与PTV外）与体重指数（BMI）、脐围（UC）和臀围（HC）的均值及方差之间的关联。进行受试者工作特征曲线分析以检验BMI、UC和HC在预测不准确摆位方面的敏感性。
在横向和垂直方向观察到BMFs与精度水平之间存在显著关联，但在纵向方向未观察到。在横向方向，与准确摆位相比，不准确摆位与更高的BMI（平均差值：约3.50 kg/m²；P = 0.001）、UC（约10 cm）和HC（约8 cm）相关（P < 0.001）。在垂直方向，与准确摆位相比，不准确摆位（>0.7 cm边界[截断值I]）与更高的BMI（平均差值 = 7.4 kg/m²；P = 0.001）、UC（5.3 cm；P < 0.001）和HC（16.0 cm；P < 0.001）相关。受试者工作特征曲线分析表明，BMI > 31.4 kg/m²可预测垂直方向不准确摆位，对于截断值I的敏感性为90.0%。此外，BMI > 30.3 kg/m²可预测横向方向不准确摆位，对于截断值II的敏感性为92.5%。
妇科肿瘤放射治疗摆位的准确性对患者的BMI高度敏感，尤其是在横向和垂直方向。我们建议，对于BMI > 30.3 kg/m²的患者应应用每日锥形束计算机断层扫描，并采用剂量较低且图像质量相当的定制方案。
