Xerostomia is defined as "the subjective sensation of dryness of the mouth". It is common
in patients with acute/chronic medical conditions, especially in patients with cancer.
Results from observational studies reported 40% to 75% prevalence of xerostomia among
cancer patients. Head and neck cancer patients, as the seventh most common type of
cancer, reported an even higher prevalence (80%) of xerostomia after treatment compared
with other cancer types. Despite the high prevalence of xerostomia, it is often
underrecognized by patients and healthcare providers.
Xerostomia in head and neck cancer patients is largely induced by radiation in the head
and neck region, which can damage salivary glands, and thereby change the volume,
consistency, and pH of their saliva. Besides, xerostomia may be caused or exacerbated by
the concomitant or sequential use of chemotherapy agents and other drugs (e.g., opioid).
Consistent lacking saliva in cancer patients can lead to increased risk of oral fungal
infection, caries, swallowing problems, sleep problems, depression, fatigue and altered
taste, which may even result in poor nutritional status. Furthermore, xerostomia may
become a chronic and even irreversible side effect.
Current therapies for xerostomia in cancer patients include both pharmacological and
non-pharmacological treatments. Pharmacotherapy has been considered as a general
treatment for stimulating saliva secretion in alleviating xerostomia for head and neck
cancer patients. However, the evidence of pharmacological interventions (e.g.,
pilocarpine, bethanechol, amifostin, cevimeline and palifermin) on xerostomia is
insufficient, and the use of pharmacotherapy may cause some common adverse effects,
including nausea, sweating, nervousness, and urinary frequency. Non-pharmacological
treatments such as saliva stimulants (e.g. citric and malic acids, chewing gum,
toothpaste and lozenges) and saliva substitute (e.g. liquids, gels and sprays) have also
been suggested to treat xerostomia, but neither with sufficient evidence of significant
effect, and may also lead to adverse effects (e.g., nausea, unpleasant taste, diarrhea,
and tooth mineralization). Some patients may find regular sips of water useful, but only
for temporary benefit, because saliva is a complex substance with irreplaceable functions
(antibacterial and immunologic protection). Therefore, an evidence-based effective
strategy with few adverse events is warranted for head and neck cancer patients with
xerostomia.
Both acupressure and acupuncture aim to improve health and cure illnesses by improving
energy flow through stimulating meridian points. Acupressure is a non-invasive technique
of activating acupoints using hands, fingers, or thumbs along the meridians, while
acupuncture involves the use of needles. Stimulation on acupoints may increase the flow
of blood and qi along the related meridians, as well as stimulate the local blood flow
around the salivary glands, thereby increasing salivary secretion. Also,
acupressure/acupuncture may stimulate the parasympathetic nervous system, hence
indirectly stimulate salivary glands secretion. Besides, microcirculation may be promoted
through the release of sensory neuropeptides, so as to increase the tissue oxygenation
and metabolism. Some studies had demonstrated positive effect of acupuncture on
xerostomia for head and neck cancer patients, while none examined acupressure. Based on
the same meridian theory, both acupuncture and acupressure were widely applied to the
symptom management (e.g. fatigue, nausea, pain) for cancer patients, effectively with
good adherence. Compared to acupuncture, acupressure can be administered by patients
themselves after training. The purpose of this study is to examine the effect of
self-administered acupressure on xerostomia for head and neck cancer patients.