Department of Radiation Oncology, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina.
Department of Otolaryngology, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina; Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina.
Pract Radiat Oncol. 2013 Oct-Dec;3(4):282-6. doi: 10.1016/j.prro.2012.10.001. Epub 2012 Nov 2.
To quantify the effect of sparing the primary site after transoral laser microsurgery (TLM) for oropharyngeal squamous cell carcinoma (OPSCC).
We reviewed 4 patients with OPSCC who were treated with TLM and postoperative radiation. All patients had T1 base of tongue primaries with the following N stages: 1 N1; 2 N2a; and 1 N2b. Three were lateralized to the right and 1 lateralized to the left. The primary site was not spared initially. We created new intensity modulated radiation treatment (IMRT) plans that spared the primary site. The prescribed dose to the high-risk (HR) and standard-risk (SR) planning target volumes (PTVs) was 60 Gy and 46 Gy at 2 Gy/fraction. PTV-SR and PTV-HR were adjusted to exclude the primary site. The primary site was maximally spared while maintaining similar PTV coverage and normal tissue avoidance as the initial plan. Dosimetric comparisons were made between the initial and primary-site sparing IMRT plans.
Dosimetric coverage of the PTVs and normal tissues (pharyngeal constrictors, contralateral parotid, etc) were comparable. The mean dose to the primary site was reduced by 20 Gy. The mean dose to the oral cavity was reduced by 25 Gy.
This study suggests that omitting the primary site from the radiation therapy target volume is unlikely to reduce long-term swallowing function to a meaningful degree in patients who receive radiation therapy following TLM for base of tongue cancer.
定量分析经口激光微创手术（TLM）治疗口咽鳞状细胞癌（OPSCC）后保留原发部位的效果。
我们回顾了 4 例接受 TLM 和术后放疗的 OPSCC 患者。所有患者的原发部位均为 T1 舌基底，且具有以下 N 分期：1 例 N1；2 例 N2a；1 例 N2b。3 例向右侧偏位，1 例向左侧偏位。最初未保留原发部位。我们创建了新的调强放疗（IMRT）计划，以保留原发部位。高危（HR）和标准风险（SR）计划靶区（PTV）的规定剂量为 60 Gy 和 46 Gy，每次 2 Gy。PTV-SR 和 PTV-HR 进行调整以排除原发部位。在保持与初始计划相似的 PTV 覆盖范围和正常组织回避的同时，最大程度地保留原发部位。对初始和原发部位保留的 IMRT 计划进行了剂量学比较。
PTV 和正常组织（咽缩肌、对侧腮腺等）的剂量学覆盖情况相当。原发部位的平均剂量降低了 20 Gy。口腔的平均剂量降低了 25 Gy。
本研究表明，在接受 TLM 治疗舌底癌后接受放疗的患者中，将原发部位从放疗靶区中排除不太可能在很大程度上降低长期吞咽功能。
