Emerging understanding of dosimetric factors impacting on dysphagia and nutrition following radiotherapy for oropharyngeal cancer

Abstract

The relationships observed between known dosimetric constraints and functional outcomes highlight the potential for dosimetric data to assist in prognosis and treatment. Systematic research is required to refine dosimetric parameters and the impact on functional outcomes.

Dysphagia and trismus after concomitant chemo-Intensity-Modulated Radiation Therapy (chemo-IMRT) in advanced head and neck cancer; dose–effect relationships for swallowing and mastication structures

“…Besides, objective and subjective problems do not have to occur simultaneous. In accordance with Roe et al, and Cartmill et al [1,16], we conclude that measuring at different time points with inclusion of baseline measurements is important to see how dose relationships vary over time and which severe functional problems already exist before treatment, likely caused by the tumor.…”

“…The structures involved in mastication are the pterygoid, masseter, and temporalis muscles, and the mandibular condyle [13]. Restricted and/or painful mouth opening affect normal chewing and eating, and impair speech and oral hygiene [14,15] Studies that focused on radiation dose reduction and or structure avoidance, unfortunately, cannot easily be compared, because of their heterogeneity in tumor sites and treatment protocols, their overall retrospective nature, and their lack of objective assessments [1,16]. A systematic review of Roe et al [1] (papers published between January 1998 and December 2009) found only one prospective longitudinal study that consistently evaluated oropharyngeal swallow function, using both objective instrumental measures, as well as patient self-reports alongside established toxicity scores [17].…”

“…Also, other recently published reviews e.g. , Cartmill (2012), Nutting (2012), Bhide (2012) and colleagues, concluded that although the evidence is small, a number of dosimetric constraints might be influential in minimizing the negative impact on swallowing, and potentially on nutritional outcomes [4,5,16,18] .…”

“…However, the number of significant methodological weaknesses in the current available literature must be acknowledged when interpreting the data, and Cartmill et al, therefore, suggested that future studies examining the predictive power of dosimetric factors need to include pretreatment data, and a more standardized, validated measurement protocol [16].…”

Physiological Changes to the Swallowing Mechanism Following (Chemo)radiotherapy for Head and Neck Cancer: A Systematic Review

“…Eisbruch et al [32] were the first to postulate a set of dysphagia/aspiration-related structures (DARS) -deglutitive structures whose damage was deemed likely to cause dysphagia and aspiration, as observed on videofluroscopy, and demonstrated radiation-induced structural changes in posttreatment CT scans. Recent review papers have reported these DARS to include the: superior, middle and inferior pharyngeal constrictors, glottic and supraglottic larynx and its adductor muscles, upper esophageal sphincter and mucosal/submucosal surfaces of the BOT [53,54].…”