Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
Pract Radiat Oncol. 2012 Jul-Sep;2(3):201-209. doi: 10.1016/j.prro.2011.10.001. Epub 2011 Nov 15.
The Radiation Therapy Oncology Group (RTOG) has published consensus guidelines for contouring relevant anatomy for postmastectomy radiation therapy (RT). How these contours relate to current treatment practices is unknown. We analyzed the dose-volume histograms (DVHs) for these contours using current clinical practice at University of Texas MD Anderson Cancer Center and compared them with the proposed treatment plans to treat RTOG-defined targets to full dose.
We retrospectively analyzed treatment plans for 20 consecutive women treated with postmastectomy RT for which the treatment targets were the chest wall (CW), level III axilla (Ax3), supraclavicular (SCV), and internal mammary (IM) nodes. The RTOG consensus definitions were used to contour the following anatomic structures: CW; level I, II, and III axillary nodes (Ax1, Ax2, Ax3); SCV; IM; and heart (H). DVHs for these contours and the ipsilateral lung were generated from clinically designed treatment that had actually been delivered to each patient. For comparison regarding dose to normal tissue, new treatment plans were generated with the goal of covering 95% of the anatomic contours to 45 Gy.
The prescribed dose was 50 Gy in each case. The mean percent of volumes that received 45 Gy (V45) for the RTOG guideline-based contours were CW 74%, Ax1 84%, Ax2 88%, Ax3 96%, SCV 84%, and IM 80%. Mean heart V10 values were 11% for treatment of left-sided tumors and 6% for right-sided tumors. Mean ipsilateral lung V20 values were 28% for left-sided tumors and 34% for right-sided tumors. For the contour-based plans, mean V45 values were CW 94%, Ax1 95%, Ax2 97%, Ax3 98%, SCV 98%, and IM 85%. Mean heart V10 values were 14% for treatment of left-sided tumors and 12% for right-sided tumors. Mean ipsilateral lung V20 values were 32% for left-sided tumors and 45% for right-sided tumors.
Clinically derived treatment plans, which have proven efficacy and are the current standard, cover 74% to 96% of the anatomy-based RTOG consensus volumes to the prescription dose. This discrepancy should be considered if treatment planning protocol guidelines are designed to incorporate these new definitions.
放射治疗肿瘤学组（RTOG）已经发布了用于乳腺癌根治术后放射治疗（RT）相关解剖结构勾画的共识指南。这些轮廓与当前治疗实践的关系尚不清楚。我们使用德克萨斯大学 MD 安德森癌症中心当前的临床实践分析了这些轮廓的剂量-体积直方图（DVH），并将其与建议的治疗计划进行了比较，以对 RTOG 定义的靶区进行全剂量治疗。
我们回顾性分析了 20 例接受乳腺癌根治术后 RT 治疗的连续女性患者的治疗计划，这些患者的治疗靶区包括胸壁（CW）、腋窝 3 区（Ax3）、锁骨上（SCV）和内乳（IM）淋巴结。采用 RTOG 共识定义来勾画以下解剖结构：CW；腋窝 I、II 和 III 区淋巴结（Ax1、Ax2 和 Ax3）；SCV；IM；以及心脏（H）。从每个患者实际接受的临床设计治疗中生成了这些轮廓和同侧肺的 DVH。为了比较正常组织的剂量，生成了新的治疗计划，目标是将 95%的解剖轮廓覆盖到 45Gy。
每个病例的处方剂量均为 50Gy。基于 RTOG 指南的轮廓，接受 45Gy 的体积百分比（V45）的平均值分别为 CW 74%、Ax1 84%、Ax2 88%、Ax3 96%、SCV 84%和 IM 80%。左侧肿瘤治疗的平均心脏 V10 值为 11%，右侧肿瘤为 6%。左侧肿瘤治疗的平均同侧肺 V20 值为 28%，右侧肿瘤为 34%。对于基于轮廓的计划，CW 的平均 V45 值为 94%，Ax1 为 95%，Ax2 为 97%，Ax3 为 98%，SCV 为 98%，IM 为 85%。左侧肿瘤治疗的平均心脏 V10 值为 14%，右侧肿瘤为 12%。左侧肿瘤治疗的平均同侧肺 V20 值为 32%，右侧肿瘤为 45%。
已经证明疗效且是当前标准的临床衍生治疗计划，将基于解剖结构的 RTOG 共识体积的 74%至 96%覆盖到处方剂量。如果设计治疗计划协议指南以纳入这些新定义，则应考虑这种差异。
