Mulla Zaheeda, Iskanderani Omar, Weber Amina, AlMohamad Abdullah, Al-Amoodi Mohammed Sheikh, Soaida Shamel
Department of Oncology, King Faisal Specialist Hospital and Research Center, Jeddah, Saudi Arabia.
Department of Oncology, King Abdulaziz University, Jeddah, Saudi Arabia.
Adv Radiat Oncol. 2020 Oct 14;6(1):100592. doi: 10.1016/j.adro.2020.09.025. eCollection 2021 Jan-Feb.
This study aimed to compare thermoplastic mask with bra in terms of setup reproducibility and immobilization of pendulous breasts during radiation therapy (RT).
Forty-two female patients with breast cancer treated with either intensity modulated RT or 3-dimensional conformal RT were retrospectively reviewed. Of these, 21 benefited from thermoplastic mask immobilization and 21 used a bra. Setup accuracy was evaluated using consecutive cone beam computed tomography/electronic portal imaging device sessions over the first 3 days before treatment (systematic setting), followed by weekly cone beam computed tomography/electronic portal imaging device (random settings), and compared with the reference image to calculate the corresponding translational shift (setup error) in the 3 planes. Average absolute shift values in both systematic and random settings were compared between the 2 groups. Accuracy was analyzed by comparing the percentage of pooled settings within ±0.05 and ±0.1 cm of the reference image.
Compared with a bra, use of the mask was associated with a smaller longitudinal shift in systematic settings (difference in mean: 0.27 cm; = .027; Mann-Whitney test) and a lesser lateral shift in random setting (difference in mean: 0.19 cm; = .005; Mann-Whitney test). In the pooled systematic settings, the mask performed relatively better than the bra in the lateral and longitudinal planes, with no statistical significance. In pooled random settings, mask showed greater accuracy than bra in the lateral plane with 86.0% versus 58.9% accuracy at ±0.5 cm ( < .001) and 48.8% versus 21.7% accuracy at ±0.1 cm ( < .001), respectively. There was no significant difference in the incidence of radiodermatitis between the 2 groups. However, a hypofractionation regimen was associated with a lower incidence of radiodermatitis, and the severity of skin reactions was positively correlated with treatment dose (unstandardized regression coefficient: B = .001; correlation coefficient: = .571; < .001).
Masks provide superior reproducibility compared with commercially available bras.
本研究旨在比较热塑性面罩与胸罩在放射治疗（RT）期间下垂乳房的摆位重复性和固定效果。
回顾性分析42例接受调强放疗或三维适形放疗的女性乳腺癌患者。其中，21例受益于热塑性面罩固定，21例使用胸罩。在治疗前的前3天使用连续的锥束计算机断层扫描/电子射野影像装置（系统设置）评估摆位精度，随后每周进行锥束计算机断层扫描/电子射野影像装置（随机设置），并与参考图像比较以计算3个平面上相应的平移偏移（摆位误差）。比较两组在系统设置和随机设置中的平均绝对偏移值。通过比较参考图像±0.05 cm和±0.1 cm范围内合并设置的百分比来分析准确性。
与胸罩相比，在系统设置中使用面罩纵向偏移较小（平均差值：0.27 cm；P = 0.027；Mann-Whitney U检验），在随机设置中外侧偏移较小（平均差值：0.19 cm；P = 0.005；Mann-Whitney U检验）。在合并的系统设置中，面罩在外侧和纵向平面上的表现相对优于胸罩，但无统计学意义。在合并的随机设置中，面罩在外侧平面上显示出比胸罩更高的准确性，在±0.5 cm处准确性分别为86.0%和58.9%（P < 0.001），在±0.1 cm处准确性分别为48.8%和21.7%（P < 0.001）。两组放射性皮炎的发生率无显著差异。然而，大分割放疗方案与较低的放射性皮炎发生率相关，皮肤反应的严重程度与治疗剂量呈正相关（非标准化回归系数：B = 0.001；相关系数：r = 0.571；P < 0.001）。
与市售胸罩相比，面罩具有更好的重复性。
