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.
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
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.