CHAPTER 37 CANCER OF THE LARYNX The larynx is divided, for purposes of tumour classification, into three regions—supraglottis, glottis and subglottis (Fig. 82). The supraglottis includes the laryngeal surface of the epiglottis, ary-epiglottic folds, arytenoids, false cords and ventricle. The lingual surface of the epiglottis and vallecula are in the oropharynx. The glottis comprises the vocal cords and the anterior and posterior commissures. The lymphatic drainage of the larynx (Fig. 83) is compartmentalized into the above regions. The glottis has virtually no lymphatic drainage and so acts as a watershed. The area above the vocal cords drains upwards via the superior lymphatic pedicle to end in the upper deep cervical chain. The subglottis drains both to the prelaryngeal and paratracheal glands. Tumours of the larynx are classified according to the U.I.C.C. T.N.M. system, but it is beyond the scope of this book to detail the system. It is of little value in a tumour with such a relatively low incidence as laryngeal cancer. It is of much more value to be acquainted with the surgical pathology and behaviour of cancer in the various laryngeal regions. Ninety-nine per cent of laryngeal cancer is squamous carcinoma and it is much more common in males and smokers. SUPRAGLOTTIC CANCER PATHOLOGY. These tumours usually present in one of three ways: (a) as a large exophytic tumour on the laryngeal surface of the epiglottis; (b) as a relatively small discrete growth on the ary-epiglottic fold; and (c) as an isolated ulcerative growth on the false cord. The supraglottic space has a rich lymphatic drainage and a high proportion of these tumours spread to lymph nodes. Roughly 1 in 3 epiglottic tumours, 3 out of 4 ary-epiglottic tumours and about half the false cord tumours metastasize. Nearly all these tumours will invade the pre-epiglottic space but only a small proportion will involve the vocal cords until late in the course of the disease. This fact makes partial laryngectomy a distinct possibility in supraglottic cancer. SYMPTOMS. These tumours do not affect the vocal cord and so rarely present with hoarseness. If the tumour is very large there will be some muffling of the voice. Occasionally the ary-epiglottic tumours will present with painful dysphagia or on account of a lump in the neck from a metastatic gland. In other words, these tumours are often diagnosed late since the supraglottis is not a region to give rise to early symptoms. Sometimes, in fact, tumours in the supraglottis axe discovered accidentally by an anaesthetist during intubation for another procedure.