Klaske van Sluis

6 1.2. Head and Neck Cancer 1.2 Head and Neck Cancer Head and neck cancer accounts for approximately 5% of all malignant tumours and includes cancer of the oral cavity, pharynx, larynx and oropharynx [1, 2]. Every year, 140.000 people in Europe are diagnosed with head and neck cancer, of which 40.000 are diagnosed with larynx cancer [3]. In the Netherlands both laryngeal and hypo-pharyngeal cancers are typically squamous cell carcinomas. The peak age for these cancers is between 55 and 74 years. Both cancers are more often diagnosed in men than in women (4:1), although the incidence among men is decreasing and the incidence among women is stable or slightly increasing [4]. 1.3 Functions of the larynx The larynx has a crucial part in basic physical functions including breathing, speaking and swallowing. Air which is inhaled via the nose or mouth passes the larynx when entering the trachea and lungs. The air is humidified and warmed by the upper respiratory tract. The larynx can produce sound; it is also referred to as the voice box, since the vocal folds are situated within it. During the phonatory process, air is ejected from the lungs through the glottis; the vocal folds move closer together which results in oscillation of the vocal cords [5]. The volume of the voice is determined by the pressure of the pulmonary air blown through the vocal folds, whilst the fundamental frequency (pitch) is defined by the frequency of the mucosal waves [5]. The quality of the voice depends on the myoelastic characteristics of the vocal folds, degree of vocal fold closure, irregularities during oscillation, and resonance characteristics [5, 6]. The generated voice can be articulated into speech with help of the structures in the pharynx, mouth and lips. This process of speech production can be described according to the source-filter theory [7]. This theory states that speech is a representation of the produced sound source (e.g. voice) which is formed into speech by the resonators (oral cavities, nasal cavaties) and the articulators (tongue, teeth and lips) functioning as a filter. For intake of food and drinks, the larynx has an important role during swallowing. Within the act of swallowing the epiglottis covers the entrance of the larynx which protects the airway for aspiration. In Figure 1.1 a schematic drawing of the lateral view of the normal anatomy is shown with the larynx in situ. 1.4 Total laryngectomy A total laryngectomy refers to an organ-sacrificing surgery that can be indi- cated for laryngeal and hypo-pharyngeal cancers. An indication depends on the degree of invasiveness (indicated with T-stage), size, site and recurrence of the cancer, laryngeal functionality, the patient’s condition and patient’s and doc-