Eisbruch Avraham, Levendag Peter C, Feng Felix Y, Teguh David, Lyden Teresa, Schmitz Paul I M, Haxer Marc, Noever Inge, Chepeha Douglas B, Heijmen Ben J
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI 48109-0010, USA.
Int J Radiat Oncol Biol Phys. 2007;69(2 Suppl):S40-2. doi: 10.1016/j.ijrobp.2007.04.083.
Dysphagia is a major late complication of intensive chemoradiotherapy of head and neck cancer. The initial clinical results of intensity-modulated radiotherapy (IMRT), or brachytherapy, planned specifically to reduce dysphagia are presented.
Previous research at Michigan University has suggested that the pharyngeal constrictors and glottic and supraglottic larynx are likely structures whose damage by chemo-RT causes dysphagia and aspiration. In a prospective Michigan trial, 36 patients with oropharyngeal (n = 31) or nasopharyngeal (n = 5) cancer underwent chemo-IMRT. IMRT cost functions included sparing noninvolved pharyngeal constrictors and the glottic and supraglottic larynx. After a review of published studies, the retropharyngeal nodes at risk were defined as the lateral, but not the medial, retropharyngeal nodes, which facilitated sparing of the swallowing structures. In Rotterdam, 77 patients with oropharyngeal cancer were treated with IMRT, three dimensional RT, or conventional RT; also one-half received brachytherapy. The dysphagia endpoints included videofluoroscopy and observer-assessed scores at Michigan and patient-reported quality-of-life instruments in both studies.
In both studies, the doses to the upper and middle constrictors correlated highly with the dysphagia endpoints. In addition, doses to the glottic and supraglottic larynx were significant in the Michigan series. In the Rotterdam series, brachytherapy (which reduced the doses to the swallowing structures) was the only significant factor on multivariate analysis.
The dose-response relationships for the swallowing structures found in these studies suggest that reducing their doses, using either IMRT aimed at their sparing, or brachytherapy, might achieve clinical gains in dysphagia.
吞咽困难是头颈部癌强化放化疗的主要晚期并发症。本文展示了专门为减少吞咽困难而设计的调强放射治疗（IMRT）或近距离放射治疗的初步临床结果。
密歇根大学之前的研究表明，咽缩肌、声门和声门上喉可能是因放化疗损伤而导致吞咽困难和误吸的结构。在密歇根大学的一项前瞻性试验中，36例口咽癌（n = 31）或鼻咽癌（n = 5）患者接受了化疗IMRT。IMRT的成本函数包括保留未受累的咽缩肌和声门和声门上喉。在回顾已发表的研究后，将有风险的咽后淋巴结定义为外侧而非内侧的咽后淋巴结，这有助于保留吞咽结构。在鹿特丹，77例口咽癌患者接受了IMRT、三维放疗或传统放疗；其中一半还接受了近距离放射治疗。吞咽困难的终点指标在密歇根大学的研究中包括视频荧光吞咽造影和观察者评估的评分，在两项研究中均包括患者报告的生活质量指标。
在两项研究中，上咽缩肌和中咽缩肌的剂量与吞咽困难终点指标高度相关。此外，在密歇根大学的系列研究中，声门和声门上喉的剂量也具有显著意义。在鹿特丹的系列研究中，近距离放射治疗（降低了吞咽结构的剂量）是多变量分析中唯一的显著因素。
这些研究中发现的吞咽结构的剂量反应关系表明，使用旨在保留这些结构的IMRT或近距离放射治疗来降低其剂量，可能会在吞咽困难方面取得临床改善。
