PD-0092: The dose to the larynx elevation and tongue retraction muscles has a large impact on post- radiation dysphagia

Functional Swallowing Units (FSUs) as organs-at-risk for radiotherapy. PART 1: Physiology and anatomy

“…Furthermore, the concept of Functional Swallowing Units (FSU) provides a theoretical basis for upcoming papers on radiation-induced dysphagia, focusing on clinical relevance of hyolaryngeal elevation and tongue function as well as for more advanced CT-based delineation guidelines for all FSUs (PART 2 of this series). Both papers (PART 1 and PART 2) are result of longer learning process, supported by prospectively collected data (including videofluoroscopy), pilot analyses, testing the hypothesis of relevance of defined FSUs, and encouraging preliminary results [16].…”

“…Therefore, limited data exist on the dose-effect relationship for HLE and TBR structures. In a pilot study, the analysis of our own prospectively collected data, showed that the dose to some components of aforementioned FSUs correlated significantly with subjective dysphagia outcomes, indicating that the dose to these structures may be at least as relevant as the dose to pharyngeal constrictors or the larynx [16]. Meanwhile, results of two other retrospective studies revealed that floor of mouth and tongue muscles are indeed relevant for the development of radiation-induced dysphagia [17,25,45].…”

“…On the other hand, selected PROMS correlate with the dose to the tong muscles and there is also enough data suggesting a profound role of the dose to pharyngeal constrictor muscles in developing diet alterations (i.e. RTOG physician-rated dysphagia) [16,46,47]. The relevance of dose to a certain structure is usually determined by its contribution to the best performing NTCP model for a particular endpoint.…”

“…The tongue motion FSUs were considered relevant based on their potential impact on subjective swallowing complaints of radiotherapy patients. [16,17] Following their definition, a detailed description of the anatomy for each FSU is provided. This functional approach, based on the anatomy as well as on physiology, provides the theoretical basis for the delineation guidelines of FSUs, described in detail in a separate paper (PART 2).…”

Functional Swallowing Units (FSUs) as organs-at-risk for radiotherapy. PART 2: Advanced delineation guidelines for FSUs

“…This paper, in combination with the aforementioned atlas for SWOARs, covers almost all structures involved in most of the pharyngeal swallowing components: hyolaryngeal elevation, tongue base retraction, laryngeal closure, upper oesophageal sphincter opening and pharyngeal contraction [31]. Moreover, we provide delineation guidelines for other tongue muscles (involved in tongue motion), as these muscles may be relevant if correlated with subjective swallowing complaints [17,32]. Presented concept not only complements the guidelines previously published by Christianen et al, but also makes the delineation feasible, due to a smart definition of Organs At Risk.…”