Open Journal of Stomatology, 2013, 3, 486-491 OJST
http://dx.doi.org/10.4236/ojst.2013.39079 Published Online December 2013 (http://www.scirp.org/journal/ojst/)
Dysphagia in head and neck cancer: A review
Roxana Moayer, Uttam Sinha
Department of Otolaryngology—Head & Neck Surgery, Keck School of Medicine, Los Angeles, USA
Received 1 October 2013; revised 13 November 2013; accepted 26 November 2013
Copyright © 2013 Roxana Moayer, Uttam Sinha. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Head and neck cancers are frequently associated with
dysphagia. Both pre-treatment and post-treatment
etiologies have been described in the literature. The
result of dysphagia has been well-documented as caus-
ing reductions in both quality-of-life and physical well-
being. The goal of this review is to consolidate the
current understanding of the relationship between
head and neck cancers and dysphagia.
Keywords: Dysphagia; Deglutition; Otolaryngology
1. INTRODUCTION
Dysphagia is a common, yet, understudied phenomenon.
It has been well established that dysphagia has an enor-
mous impact on both the overall quality-of-life and
health of patients. Patients with head and neck cancers
comprise a significant number of those affected by dys-
phagia. According to the Nation al Cancer Institute’s Sur-
veillance, Epidemiology, and End Results (SEER) pro-
gram, the most recent age-adjusted incidences of oral/
oropharyngeal cancer, laryngeal cancer, esophageal can-
cer, and thyroid cancer are 10.8, 3.3, 4.25, and 13.21 per
100,000, respectively [1]. These values reflect individu-
als at risk of developing dysphagia. Furthermore, dys-
phagia is not only a manifestation of head and neck can-
cer, but also a complication of cancer treatment. This
suggests that dysphagia is a salient issue for a much lar-
ger population than previously recognized. The goal of
this paper is to consolidate current understanding of the
etiology and impact of dysphagia in head and neck can-
cer patients. Ultimately, our goal is to provide a new
baseline understanding from which further innovations in
therapy can develop. In order to do this, it is necessary to
begin by reviewing normal swallow function.
2. SWALLOW SEQUENCE
Magendie is largely credited with the current, three-
phase description of deglutitio n [2]. The phases represen t
a necessary oversimplification of deglutition. In reality,
deglutition is a flu id and con certed act with some ove rlap
of the phases. The 3-phase description is, however, help-
ful for at least two reasons. First, each delineation grossly
reflects innervation patterns and the muscles which are
predominantly active during a given phase. Second, the
subdivisions provide a convenient nomenclature to dis-
cuss sites of dysfunction or breakdown in the swallow
apparatus. Various investigators have developed alternate
deglutition descriptions with some authors preferring a
two-phase scheme and still others pr eferring a four-phase
scheme [2-4]. For simplicity’s sake, only the three-phase
mechanism will be described below.
2.1. Oral Phase
The oral phase marks the initiation of the swallow se-
quence and is the only truly voluntary portion of the
mechanism. The structures involved in this phase include
the tongue, hard palate, soft palate, suprahyoid muscles,
orbicularis oris muscle and buccinator muscle. The ton-
gue, assisted by the suprahyoid muscles, is responsible
for shaping and propelling the bolus posteriorly. The
orbicularis oris and buccinator muscles provide closure
of the oral orifice to prevent spillage. The soft palate is
displaced inferiorly and anteriorly to provide closure of
the posterior oral cavity and to widen the nasal airway.
Increases in patient age and in bolus viscosity may
lengthen the duration of this phase. In healthy individuals,
the oral phase lasts 1 to 1.5 seconds at which point the
pharyngeal reflex is triggered [2-4].
2.2. Pharyngeal Phase
The pharyngeal phase of swallowing is an involuntary
reflex which is physiologically more complex than the
oral phase. The pharyngeal phase is unique in that it is
the only phase of deglutition during which respiration is
momentarily halted to prevent aspiration. The phase is
triggered by the glossopharyngeal nerve upon afferent

R. Moayer, U. Sinha / Open Journal of Stomatology 3 (2013) 486-491 487
input from the oropharyngeal mucosa carried by cranial
nerves IX and X. The pharyngeal phase it broken down
further into a sequence of five events listed below [2-4]:
1) Velopharyngeal closure by the palate to prevent re-
gurgitation of the bolus through the nasal cavity.
2) Retraction of the tongue base to further propel the
bolus.
3) Pharyngeal retraction occurs as a peristaltic wave to
clear residual contents left behind the bolus.
4) Elevation and closure of the larynx, mediated by the
strap muscles, suprahyoid muscles, submental muscles,
and laryngeal vocal fold muscles, is directly responsible
for airway protection.
5) Opening of the upper esophageal sphincter (UES)
allows passage of the bolus into the esophagus and oc-
curs by relaxation of the cricopharyngeus muscle.
The opening of th e UES marks the transition from the
pharyngeal phase of deglution to the esophageal phase.
The pharyngeal phase typically lasts 1 second in the
healthy individual and is the least variable of all the
phases [2-5].
2.3. Esophageal Phase
The esophageal phase is the final and most variable
phase of deglutition, lasting from 8 to 20 seconds in
healthy individuals. The primary function of the eso-
phageal phase is to propel the bolus through the lower
esophageal sphincter (LES) and into the stomach. This
occurs by peristaltic contraction under mixed autonomic
and somatic control in the upper one third of the eso-
phagus. Purely autonomic control occurs in the lower
two thirds of the esophagus. The esophageal phase is
complete once the bolus has passed through the LES
[2-4].
3. MEASUREMENT OF DYSPHAGIA
The complexity of the swallow function is what makes
its study so difficult. It has been noted that dysphagia has
been studied far less than other basic survival functions
such as respiration or ambulation [3]. For these reasons,
no single measurement modality has provided th e variety
of data needed to fully characterize dysphagia. Instead,
several modalities have been developed to quantify
various aspects of swallow function in clinical settings.
3.1. Videoflu or oscopy
Videofluoroscopic swallow study (VFSS) has been the
gold standard for evaluation of dysphagia since the
1980s [6]. VFSS is performed by radiographically re-
cording the anatomic structures and real-time function of
the mouth, pharynx, and esophagus. This occurs while
the patient it asked to take a liquid bolus of known vis-
cosity. Radiographic evaluation with a jog-wheel is nec-
essary to identify the site of dysfunction through frame-
by-frame analysis of the swallow mechanism [6]. Ad-
vances in imaging resolution through the last two dec-
ades have significantly enhanced the sensitivity and
specificity of VFSS. Image intensifiers in digital imaging
systems improve image resolution and thus interpretation
accuracy of VFSS data [6].
Interpretation is one drawback of VFSS. Several scales
have been developed to objectify the interpretation of
VFSS. Reference [7] evaluated the inter-rater reliability
of Videofluoroscopic Dsyphagia Scale (VDS). The scale
consists of 14 items each of which can be classified as a
measure of oral, pharyngeal, or esophageal function.
Reference [7] found low reliability of all oral phase pa-
rameters. Pharyngeal and esophageal parameters demon-
strated respectively higher inter-rater reliability, however
total score reliability according to intra-class correlation
coefficient was only 0.556. To maximize utility, it is im-
perative that videofluoroscopic data be interpreted under
the supervision of a high ly experienced provider.
3.2. Manometry
Manometry is the gold standard for the assessment of
esophageal muscular contraction. Manometry was de-
veloped in the 1950s to record esophageal muscle con-
traction in patients with dysphagia. Manometry has pri-
marily been used to evaluate patients with gastroeso-
phageal reflux disease, achalasia, and dysphagia follow-
ing gastric band placement. Concurrent use of video-
fluoroscopy enhances the ability to detect functional
success of bolus transport [8].
The original manometric studies recorded pressures
via esophageal electrodes spaced 5 centimeters apart to
generate a graph of pressures over time. Over the course
of several decades, manometry has progressed from
fluid-state transducers, to solid-state transducers, to the
most recent, high-resolution manometry. High-resolution
manometry uses electrodes spaced only 1 centimeter
apart to provide fewer pressure reading gaps between
electrodes and thus more accurate pressure readings [8].
Recent literature is controversial regarding the true
benefit high-resolution manometry over conventional
manometry. Most authors site the lack of a well-estab-
lished tool for interpreting the sheer volume of pressure
signals generated by high-resolution manometry as the
greatest drawback in utility [9]. As data interpretation
catches up to the advance in technology, manometry will
provide even more useful evaluation of dysfunctional
esophageal motor segments.
3.3. Endoscopy
Endoscopy provides direct observation of the pharyngeal
phase of deglutition as the flexible scope bypasses the

R. Moayer, U. Sinha / Open Journal of Stomatology 3 (2013) 486-491 488
oral cavity. It was developed in the nineteenth century,
but has made several recent advances in technology.
Endoscopy can now be used to evaluate sensory func-
tion. This technique is known as, flexible endoscopic
evaluation of swallowing with sensory testing (FEESST).
Its suggested use is as a non-radio active altern ativ e to the
modified barium swallow study. Reference [10] used
FEESST to assess laryngopharyngeal sensory threshold
(LPST) which refers to the intensity of an air pulse
stimulus required to trigger laryngeal adductor reflex.
Their study showed a significant correlation between
LPST impairment and functional impairment.
Most recently, endoscopy has been developed as a 3D
modality. Reference [11] demonstrated that 3D endo-
scopy provided superior visualization over conventional
2D endoscopy in a case series. While this technology is
primarily geared toward surgical use, as familiarity in-
creases and cost decreases, it has the poten tial to become
a diagnostic tool.
4. HEAD & NECK CANCER CAUSES OF
DYSPHAGIA
4.1. Oral Cancer
Oral cancer is the most common site of head and neck
cancers, accounting for approximately 30% of all cases
[1]. According to NCI data collected through the SEER
program, the age-adjusted incidence of oral cancer is
10.8 per 100,000 people [1]. Half of these cases are di-
agnosed in individuals between the age of 35 and 64. The
median age at diagnosis was 62 years-old. The vast ma-
jority of oral cancer is squamous cell (greater than 80%).
Other causes include adenocarcinoma, verrucous carci-
noma, lymphoma, and Kaposi’s sarcoma [1].
Dysphagia related to oral cancer is more commonly a
post-treatment than pre-treatment phenomenon, espe-
cially when compared to laryngeal and hypopharyngeal
cancer sites [12]. Reference [12] showed that among
patients with stage III-IV oral and oropharyngeal cancer,
6% suffered pre-treatment dysphagia compared with
68% who suffered post-treatment dysphagia. A similar
study [13] reported significantly different rates of pre-
treatment swallow dysfunction between tumor sites. Pa-
tients with oral and oropharyngeal cancer had aspiration
rates of 14% and 30% respectively, while 67% of pa-
tients with laryngeal cancer and 80% with hypopharyn-
geal cancer had problems with aspiration [13].
Pre-treatment mechanisms of dysphagia in oral cancer
include mechanical obstruction, muscle weakness, and
neural invasion. Reference [14] found dysphagia to be
present in 28.2% of patients with at least stage T2 oral
cancer. Adenoid cystic carcinoma of the base of the
tongue has been reported as a rare cause of dysphagia
[15]. The paucity of literature regarding pre-treatment
dysphagia makes it difficult to ascertain the most com-
mon mechanis m responsible for pre-treatm ent dysphagia.
Post-treatment dysphagia in oral cancer is being stud-
ied extensively. Causes can be broadly categorized as
post-surgical effects or chemoradiation effects. Surgical
mechanisms include large resection defects and nerve
damage. Reference [16] recognized a need to quantify
functional outcomes following glossectomy. In an effort
to achieve this, they found that patients with tongue
strength greater than 30 kPa post-glossectomy had sig-
nificantly better functional outcomes. Chemoradiation
mechanisms include tissue fibrosis, sensory and motor
denervation, and xerostomia [16]. Post-treatment dys-
phagia related to chemoradiation will be discussed later
as a phenomenon common to treatment of all types of
head and neck cancer.
4.2. Esophageal Cancer
The age-adjusted incidence of esophageal cancers was
most recently estimated to be 4.4 per 100,000 men and
women per year. The median age at diagnosis was re-
ported to be 67 years of age [1]. Rates of esophageal
cancer vary greatly by international region, likely re-
flecting significant differences in known risk factors.
Worldwide, the rate of esophageal cancer is increasing
[17].
In the United States, a reduction in tobacco smoking
has been followed by a reduction in the rate of squamous
cell carcinoma (SCC), while increased rates of obesity
and reflux disease have been associated with a rise in
adenocarcinoma [18]. Together, SCC and adenocarci-
noma account for more than 90% of all esophageal can-
cer cases [19]. The remaining cases have been reported
to be lymphoma, more commonly non-Hodgkin’s type,
MALT, melanoma, carcinoid, and leiomyosarcoma [20].
Dysphagia is a common pre-treatment manifestation
of esophageal cancers. Many cases are not diagnosed
until the tumor burden is large enough to cause lumen
obstruction [21]. Late stage disease requires treatment by
esophagectomy with the use of neoadjuvant therapy be-
ing decided on individual case basis. The surgical man-
agement of esophageal cancer has seen a shift toward
minimally invasive techniques [22]. Reference [23] foun d
no difference in survival between open versus minimally
invasive esophagectomy. These findings were consistent
with those of other investigators [24]. Unfortunately, prog-
nosis remains poor despite advances in surgical tech-
nique and adjuvant therapies. Such poor survival has re-
sulted in little conclusion regarding how to improve dys-
phagia associated with esophageal cancer.
4.3. Laryngeal Cancer
The age-adjusted incidence of laryngeal cancer is 3.4 per

R. Moayer, U. Sinha / Open Journal of Stomatology 3 (2013) 486-491 489
100,000 men and women per year with a median age at
diagnosis of 67 years [1]. Laryngeal cancer has garnered
more attention as Human Papilloma Virus (HPV) has
emerged as a significant risk factor [25].
Laryngeal cancer may arise in the supraglottis, the
glottis, or the sub-g lottis. The g lottis is the most common
site and is more commonly associated with vocal chang-
es than with dysphagia. When dysphagia does occur, it
usually manifests itself as an increase in aspiration due to
vocal cord or epiglottic dysfunction during the pharyn-
geal phase of deglutition. In a prospective study of pa-
tients with SCC of head and neck, patients whose pri-
mary cancer site was located in the larynx suffered the
highest rate of aspiration [2 6] .
Patients with HPV develop later stage cancer at an ear-
lier age than their non-HPV counterparts [27]. Recent
studies show that the basaloid subtype of laryngeal SCC
does confer worse prognosis, and likely greater risk of
dysphagia, even after accounting for stage and site [27].
4.4. Thyr oid Cancer
The NCI reported age-adjusted incidence of thyroid can-
cers to be 12.2 per 100,000 women and men. The most
common thyroid cancer, by far, is papillary carcinoma,
which represents 70% - 85% of cases [1]. Follicular cell
carcinoma is the next most common. Medullary thyroid,
poorly differentiated, and anaplastic thyroid are far less
common. Rare forms of thyroid cancers include squa-
mous cell carcinoma, lymphoma, and sarcoma of the
thyroid. Insular thyroid carcinoma is the most recently
described form, only being recognized as a unique entity
since 1983 [28].
Thyroid disease is a common cause of dysphagia. In a
study of patients undergoing thyroidectomy, dysphagia
was the most common pre-operative complaint. Thyroid
disease causes compressive forces on the swallow appa-
ratus resulting in a progression of worsening symptoms
from globus sensation to overt dyspagia [29]. The sever-
ity of compressive symptoms directly relates to gland
size, owing to direct force by the thyroid gland. The most
common causes of thyroid related compressive symp-
toms are benign goiter, followed by papillary thyroid
carcinoma, follicular thyroid carcinoma, and thyroiditis
[29].
The presence of more severe compressive symptoms
found in patients with smaller gland sizes may be due to
underlying disease processes. This suggests that factors
in addition to gland size contribute to the development of
dysphagia. In particular, invasion and inflammation have
been implicated in the development of dysphagia. This
notion is supported by disproportionately higher rates of
dysphagia reported in patients with lymphocytic thyroid-
itis than in patients with thyroid carcinoma despite com-
parable gland size [29].
While anaplastic thyroid carcinoma comprises only
1% - 2% of thyroid carcinomas [1], patients commonly
present with dysphagia due to rapid growth and distor-
tion of normal anatomy. For this reason, patients pre-
senting with dysphagia as a primary complaint should
receive aggressive work-up to rule out malignant etiolo-
gies.
5. POST-TREATMENT DYSPHAGIA
Chemoradiation has been an empirically supported main-
stay in the treatment of head and neck cancer for over
two decades. This practice, combined with earlier age at
diagnosis and longer survival has led to a rise in the de-
velopment of post-treatment dysphagia [30]. Postchemo-
radiation mechanisms of dysphagia include tissue fibro-
sis, sensory and motor denervation, and xerostomia [16].
Reference [31] followed 112 patients at 3, 6, and 12
months post-CRT. They found that most patients suffered
the greatest functional decline between pre-treatment to 3
months post-treatment. Despite some patient’s showing
an improveme nt on objective measures of dysphagi a most,
patients did not report subjective improvement within th e
year following CRT [31].
Several modalities to prevent dysphagia and improve
functional outcomes following chemoradiation are cur-
rently under extensive study. These include use of pro-
phylactic, pre-treatment swallow therapy, use of NG-tube
in place of G-tube for feeding during treatment, and use
of intensity-modulated radiation therapy (IMRT).
In a meta-analysis, reference [32] found that 5 out of
the 6 studies examining prophylactic swallow therapy
proved the modality to be beneficial. They noted, how-
ever, that neither the cost-benefit ratio nor long term
outcomes have been studied.
In general it has been shown that use of NG tube in
place of G-tube decreases dysphagia. Maintenance of
nutrition through chemoradiation treatment is a difficult
task achieved by a diligent multi-disciplinary team. It is
thought that use of an NG-tube helps to maintain the
strength of motion of muscles involved in the swallow
mechanism. Evaluation of patients’ appropriateness for
NG-tube placement should be done on an individual and
multi-discipline basis [32].
Organ-sparing CRT does not spare the structures in-
volved in successful swallow. IMRT is being investigated
as a possible alternative to conventional CRT to spare
structures critical to successful swallow. Reference [33]
demonstrated that IMRT could successfully spare dys-
phagia/aspiration related structures (DARS), especially
the pharyngeal constrictors and th e glottic and supraglo t-
tic larynx. This resulted in significantly improved post-
treatment swallow function [32,33].

R. Moayer, U. Sinha / Open Journal of Stomatology 3 (2013) 486-491 490
6. CONCLUSION
Dysphagia is an important phenomenon in head and neck
cancer presentation and outcome. There are several fac-
tors that make study of this phenomenon difficult. First,
the swallow apparatus is a complex structure. There are
several etiologies responsible for dysphagia which may
occur at any point during the mechanism. Second, no
standard measurement exists to quantify dysphagia
across studies. Even within a given measure, there is a
lack of consensus regarding the interpretation of data.
Third, because head and neck cancers comprise such a
wide variety of neoplasms, it is difficult to generalize
findings between cancer groups. Finally, head and neck
cancers, especially once classified by region and histol-
ogy, are relatively rare. As the body of research continues
to grow, investigators must work toward consensus on
parameters such as tumor classification, functional meas-
urement, and data interpretation. Such consensus will
greatly improve the strength of studies limited in size b y
the rarity of such cancers.
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