Comparison with other studies and clinical applicability
The literature on the functional failure following primary (C)RT for advanced laryngeal cancer is scarce and oftentimes conflicting. This is partly explained by the lack of consensus on the definition of functional laryngeal failure. Earlier studies have focused on salvage laryngectomy as the key outcome, however more recent studies have emphasised the importance of accounting for all types of laryngeal dysfunction while assessing the effects of organ preservation therapies[5][6]. Our definition is based on those reported in previous studies and addresses key aspects of the laryngeal functions (airway patency, airway protection and swallow)[5]. Dysphonia was not included in the definition as the majority of the patients had vocal complaints. Over 30% of the subjects were found to have NFL in the present study, underlining the importance of careful patient counselling about the expectations of treatment. This figure is higher compared to the study by Heukelom et al. which found 21% develop NFL following (C)RT, which might be explained by a high proportion of non-laryngeal cancers and early stage (T1-T2) tumours included in that study[5].
The identification of factors associated with poor laryngeal function following CRT has been a subject of several studies, however the findings have been far from consistent[5][6]. Smoking has been found to be strongly associated with worse functional outcomes in several studies, which is echoed by our results[5][7]. Likewise, vocal cord fixation was identified to carry a significantly increased risk of locoregional failure and while CRT is still often employed is considered by many to be a marker of poor outcome[8][9]. Conversely, other factors including T stage, nodal status and pre-epiglottic extension were not found to be of a useful predictive value. This has also been shown to be of variable importance in the published literature[10][6].