Cui Taoran, Ward Matthew C, Kittel Jeffrey A, Joshi Nikhil, Koyfman Shlomo A, Xia Ping
Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, USA.
Department of Radiation Oncology, Atrium Health, Charlotte, USA.
Cureus. 2021 Sep 17;13(9):e18065. doi: 10.7759/cureus.18065. eCollection 2021 Sep.
It has been suggested that post-transoral robotic surgery (post-TORS) radiotherapy (RT) might reduce the dose to organs at risk (OARs) adjacent to the primary tumor bed; however, the evidence supporting this has yet to be sufficient. This study examined the radiation dose reduction to OARs by omitting the primary tumor bed through the use of an Auto-Planning (AP)-based workflow.
Twelve patients were identified who underwent post-TORS RT to the primary tumor bed and the unilateral/bilateral neck lymph nodes. In each patient, two treatment plans were designed: a Comprehensive (Comp)-plan treating the original planning target volume (PTV) including both the primary tumor bed and the lymph nodes, and a Neck-plan treating only the lymph nodes and omitting the primary tumor bed. Both plans were optimized using AP to ensure plan quality consistency. We compared the doses received by 95% of the primary tumor beds and lymph nodes (D95%) and our institutional dose constraints for the OARs between the Comp- and Neck-plans. Statistical analysis was performed using R Statistical Software (R Foundation for Statistical Computing, Vienna, Austria) with a two-tailed paired Wilcoxon signed-rank test.
All plans met target dose coverage requirements with at least 95% of the PTVs covered with the corresponding prescription doses. The primary tumor bed in the Neck-plans was spared with a significantly lower mean D95% (25.9 Gy vs. 60.0 Gy; p < 0.01; Wilcoxon test). The mean dose to the oral cavity (20.9 Gy vs. 28.1 Gy; p < 0.01) and the supraglottis (36.9 Gy vs. 28.2 Gy; p < 0.01) was significantly lower in the Neck-plans.
This study suggests that sparing the primary tumor bed during post-TORS RT offers dosimetric benefits to nearby OARs with significant dose reductions to the oral cavity and supraglottis. Further study of the clinical risks and benefits afforded by this strategy is needed.
有人提出，经口机器人手术后放疗（post-TORS）可能会降低原发肿瘤床附近危及器官（OARs）的剂量；然而，支持这一观点的证据尚不充分。本研究通过使用基于自动计划（AP）的工作流程省略原发肿瘤床，来研究对OARs的辐射剂量降低情况。
确定了12例接受原发肿瘤床及单侧/双侧颈部淋巴结post-TORS放疗的患者。为每位患者设计了两个治疗计划：一个综合（Comp）计划，治疗包括原发肿瘤床和淋巴结的原始计划靶体积（PTV）；一个颈部计划，仅治疗淋巴结并省略原发肿瘤床。两个计划均使用AP进行优化，以确保计划质量的一致性。我们比较了Comp计划和颈部计划中95%的原发肿瘤床和淋巴结所接受的剂量（D95%）以及我们机构对OARs的剂量限制。使用R统计软件（奥地利维也纳的R统计计算基金会）进行统计分析，采用双尾配对Wilcoxon符号秩检验。
所有计划均满足靶剂量覆盖要求，至少95%的PTV被相应的处方剂量覆盖。颈部计划中的原发肿瘤床得到了 sparing，其平均D95%显著降低（25.9 Gy对60.0 Gy；p < 0.01；Wilcoxon检验）。颈部计划中口腔的平均剂量（20.9 Gy对28.1 Gy；p < 0.01）和声门上区的平均剂量（36.9 Gy对28.2 Gy；p < 0.01）显著更低。
本研究表明，在post-TORS放疗期间省略原发肿瘤床对附近的OARs具有剂量学益处，可显著降低口腔和声门上区的剂量。需要进一步研究该策略带来的临床风险和益处。
