Department of Radiation Oncology, Maulana Azad Medical College, New Delhi, India.
Department of Medical Oncology, Gujarat Cancer and Research Institute, Ahmedabad, Gujarat, India.
J Cancer Res Ther. 2023 Jan-Mar;19(2):159-164. doi: 10.4103/jcrt.jcrt_1212_21.
Conventional field radiotherapy based on anatomical landmarks has been the traditional treatment for breast cancer. Having proven efficacy, it is still the current standard of treatment. The Radiation Therapy Oncology Group (RTOG) has published guidelines for contouring target volumes in postmastectomy patients. The impact of this guideline in the current clinical practice is less known; hence, we have analyzed dose-volume histograms (DVHs) for these plans and compared them with the proposed treatment plans to treat RTOG-defined targets.
RTOG consensus definitions were used to contour the target volumes in 20 previously treated postmastectomy patients. The prescription was 42.4 Gy in 16 fractions. DVHs were generated from clinically designed plans that had actually been delivered to each patient. For comparing dose to target volumes, new plans were generated with the goal of covering 95% of volume to 90% of prescribed dose.
In RTOG contoured Group, coverage improved for the supraclavicular (V90 = 83 vs. 94.9%, P < 0.05) and chest wall (V90 = 89.8 vs. 95.2%, P < 0.05). Axillary nodal coverage improved for Level-1(V90 = 80.35 vs. 96.40%, P < 0.05), Level-II (V90 = 85.93 vs. 97.09%, P < 0.05) and Level III (V90 = 86.67 vs. 98.6%, P < 0.05). The dose to the ipsilateral lung is increased (V20 = 23.87 vs. 28.73%, P < 0.05). Low dose to heart is increased in left-sided cases (V5 = 14.52 vs. 16.72%, P < 0.05) while same in right-sided cases.
The study shows that radiotherapy using the RTOG consensus guidelines improves coverage to target volumes with a nonsignificant increase in normal organ dose compared to that based on anatomical landmarks.
基于解剖标志的传统全野放疗一直是乳腺癌的传统治疗方法。它已被证明具有疗效，目前仍是治疗标准。放射肿瘤学组（RTOG）已发布了乳房切除术后患者靶区勾画指南。目前对于该指南在临床实践中的影响还知之甚少；因此，我们分析了这些计划的剂量-体积直方图（DVHs），并将其与拟议的治疗计划进行了比较，以治疗 RTOG 定义的靶区。
使用 RTOG 共识定义来勾画 20 例既往接受过乳房切除术的患者的靶区。处方剂量为 42.4Gy，共 16 次。从已实际应用于每位患者的临床设计计划中生成 DVHs。为了比较靶区剂量，我们生成了新的计划，目标是覆盖 95%的体积至 90%的处方剂量。
在 RTOG 勾画组中，锁骨上（V90=83%对 94.9%，P<0.05）和胸壁（V90=89.8%对 95.2%，P<0.05）的覆盖率有所提高。腋窝淋巴结水平 1（V90=80.35%对 96.40%，P<0.05）、水平 2（V90=85.93%对 97.09%，P<0.05）和水平 3（V90=86.67%对 98.6%，P<0.05）的覆盖率也有所提高。同侧肺的剂量增加（V20=23.87%对 28.73%，P<0.05）。左侧病例心脏的低剂量增加（V5=14.52%对 16.72%，P<0.05），右侧病例则相同。
该研究表明，与基于解剖标志的放疗相比，使用 RTOG 共识指南进行放疗可提高靶区覆盖率，同时正常器官剂量无显著增加。
