[Image-guided application of plant pigment patch and laser microdot ablation for surface marking in radiotherapy for breast cancer: a randomized controlled trial].

Abstract / Summary

To validate the non-inferiority of plant-based pigment patches as surface markers for postoperative radiotherapy localization in breast cancer, evaluate their accuracy, durability and safety, and identify the factors influencing pigment fading to determine the patients eligible for these patches. In this randomized controlled trial, 80 patients receiving their first course of postoperative radiotherapy for breast cancer were randomly assigned in a 1:1 ratio to plant-based pigment patch group (trial group) or conventional laser microdot tattoo group (control group). The primary outcome was 3-dimensional setup error (non-inferiority margin: 0.7 mm). The secondary outcomes included uniaxial errors, re-marking frequency, skin adverse events, patient comfort, and healthcare satisfaction. Linear mixed-effects models and Cox regression were used for data analyses. The baseline characteristics of the patients were balanced between the two groups. The trial group demonstrated non-inferiority to the control group in setup accuracy (3-dimensional error: 3.12±1.14 mm vs 3.05±0.98 mm; mean difference: 0.07 mm; 95% CI: -0.31 to 0.45; upper limit <0.7 mm). No significant differences were observed in the uniaxial errors. Patient comfort scores were significantly higher in the trial group (4.23±0.65 vs 0.15±0.82, P<0.001). The incidence of skin adverse events was zero in the trial group but 12.5% in the control group (P<0.05). Multivariable Cox regression identified oily skin (HR=2.78, P<0.001), frequent sweating (HR=3.02, P<0.001), frequent washing (HR=1.42, P<0.05), and a high BMI (HR=1.32, P<0.05) as independent risk factors for faster pigment fading, while the use of a protective agent was a protective factor (HR=0.47, P=0.019). Plant-based pigment patches are non-inferior to conventional laser microdots and offer comparable positioning accuracy with superior comfort and safety. 目的: 验证植物色素贴作为乳腺癌术后放疗体表定位标记的非劣效性，明确其定位准确性、标记持久性及安全性，探索褪色影响因素与优势适用人群，为临床提供更优体表定位标记方案。方法: 选取本中心80例乳腺癌术后首次放疗患者，随机分为植物纹身贴（试验组）与激光微点（对照组），每组40例。其中试验组（A组）对靶区体表激光投影处贴上色素贴作为标记，对照组（B组）采用二氧化碳激光微点烧灼标记。收集两组的三轴摆位误差、重复标记率、出汗/洗刷频率、防护剂使用、皮肤不良反应发生率、患者舒适度及医护满意度评分等数据。采用线性混合效应模型（LMM）及Cox比例风险模型（Cox回归）等分析方法，进行非劣效性评估及褪色因素分析。结果: 两组患者基线资料（年龄、BMI、皮肤类型、术后乳房状态等）均衡可比（P均>0.05）。主要终点方面，试验组三维合成摆位误差为3.12±1.14 mm，显著低于对照组的3.05±0.98 mm，边际均值差0.07 mm（-0.31，0.45），95% CI上限<0.7 mm，非劣效性成立;试验组标记维持时间为15.3±2.3 d，短于对照组的30.1±2.9 d（P<0.001），但平均重复标记2次（对照组1次），且重复操作无需重新定位，未增加摆位误差。次要终点显示，试验组和对照组Lat、Lng、Vrt方向单轴摆位误差无显著差异（P均>0.05）。亚组分析显示，植物色素贴的非劣效性在不同年龄、术后乳房状态亚组中均稳定存在，油性皮肤亚组摆位误差略高于中性/干性皮肤，但仍低于对照组同亚组。试验组患者舒适度评分（4.23±0.65）显著高于对照组（0.15±0.82）（P<0.001），医护满意度两组无差异（3.98±0.71 vs 4.12±0.68，P=0.387）。安全性方面，试验组皮肤不良反应发生率 0%，低于对照组的12.50%（3例1级红肿、2例2级瘙痒），组间差异具有统计学意义（P<0.05）。Cox回归分析显示，油性皮肤（HR=2.78，P<0.001）、每天出汗≥3次（HR=3.02，P<0.001）、每天洗刷次数≥2次（HR=1.42，P<0.05）、BMI（HR=1.32，P<0.05）是植物色素贴褪色的独立危险因素，而使用防护剂（HR=0.47，P=0.019）是独立保护因素;年龄、治疗剂量、治疗周期等对褪色无显著影响（P均>0.05）。结论: 植物色素贴在乳腺癌术后放疗体表定位中达到非劣效性要求，定位准确性不亚于传统激光微点标记，且具备无创、患者舒适度高、安全性良好等优势。.

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