Functional Swallowing Units (FSUs) as organs-at-risk for radiotherapy. PART 2: Advanced delineation guidelines for FSUs. (January 2019)

• Record Type: Journal Article
• Authors: Gawryszuk, Agata; Bijl, Hendrik P.; Holwerda, Monique; Halmos, Gyorgy B.; Wedman, Jan; Witjes, Max J.H.; van der Vliet, Anton M.; Dorgelo, Bart; Langendijk, Johannes A.
• Is Part Of: Radiotherapy and oncology. Volume 130(2019)
• Page Start: 68
• Page End: 74
• Publication Date: 2019-01
• Subjects: SWOARs swallowing organs at risk -- HLE hyolaryngeal elevation -- TBR tongue base retraction -- FSUs Functional Swallowing Units -- FOM floor of mouth -- THM thyrohyoid muscles -- PDS posterior digastric/stylohyoid muscles complex -- SCM sternocleidomastoid muscle -- LPM longitudinal pharyngeal muscles -- HSG hyoglossus/styloglossus muscles complex -- GGS genioglossus muscles complex -- BOT base of tongue -- ITM intrinsic tongue muscles -- NTCP normal tissue complication probability -- DVH dose–volume histogram -- PCM pharyngeal constrictor muscle -- VF videofluoroscopy; Head and neck cancer -- (chemo)Radiation -- Delineation -- Swallowing organs at risk -- Hyolaryngeal elevation -- Tongue base retraction; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2018.09.022
• Languages: English
• ISSNs: 0167-8140

Abstract

Highlights: Delineation of Functional Swallowing Units is feasible on CT and supported by MRI. Dysphagia NTCP models may be improved using new DVH data as potential predictors. Swallowing sparing strategies can be better targeted with new structures definition. Abstract: Background and purpose: In a separate article (PART 1), a rationale and explanation of the physiology-and-anatomy-based concept of Functional Swallowing Units (FSUs) was presented. FSUs are swallowing muscles not included in the set of commonly defined swallowing organs at risk (SWOARs). They are involved in three crucial swallowing components: hyolaryngeal elevation (HLE), tongue base retraction (TBR) and tongue motion. This paper is a continuation of PART 1 and it provides detailed computed tomography (CT)-based delineation guidelines for FSUs, which presumably are also at risk of radiation-induced dysphagia. Material and methods: Following analysis of swallowing physiology and human anatomy, presented in PART 1, CT-based delineation guidelines for defined FSUs were created. Delineation was performed by the first author and revised by a panel of experts. Results and conclusions: Detailed delineation guidelines are presented for seven FSUs involved in HLE, TBR and tongue motion. The guidelines are supplemented by CT and MRI-based exemplary illustrations and complete CT/MRI-based delineation atlases (available online). This paper provides information essential to the implementation of the FSU concept in radiation practice, and supports uniform contouring, data collection and further improvement of swallowing sparing radiation-based strategies.