Swallowing in head and neck cancer
Dr Mark Torres-Holmes expands on swallowing difficulties in head and neck cancer and when the use of feeding tubes is required.
Swallowing (deglutition) is a complex sequence of events, that when it goes wrong can cause significant morbidity (suffering).
Cancer in sites like the mouth, pharynx (throat) and larynx (voice box) can result in difficulty swallowing.
The treatments for head and neck cancer often involve surgery, radiation and chemotherapy, or combinations thereof, and any of these treatments can also cause difficulty swallowing.
Swallowing is divided into four stages: oral preparatory, oral transfer, pharyngeal and oesophageal phases that follow each other in sequence.
1. The oral preparatory stage
- Where we chew and mix food with saliva to prepare into a bolus of suitable size and consistency.
- The parts of the mouth critical here are the teeth, tongue, cheeks and hard palate.
2. Oral transfer stage
- Involuntary reflexes in the mouth help prepare the food bolus to be swallowed.
3. The pharyngeal stage
- Involuntary reflexes move the bolus through the throat.
- The three critical events here are that food is prevented from going up the nose, prevented from coming back into the mouth and prevented from entering the airway.
- The critical structures are the base of the tongue, the soft palate, the muscular tonsil pillars, the pharyngeal constrictor muscles, the larynx including the epiglottis, arytenoids and true vocal cords and the upper oesophageal sphincter (valve).
4. The oesophageal stage
- The oesophagus, including the lower oesophageal sphincter, relaxes to receive the bolus.
- Peristaltic contractions move the bolus into the stomach.
The term dysphagia refers to swallowing difficulty but does not specify where the swallowing problem is. Odynophagia refers to pain when swallowing, and aspiration means that what we swallow goes into the airway.
Usually a good history and examination by a head and neck surgeon can identify the problem sites. Sometimes a modified barium swallow imaging study is necessary.
Any surgery involving the mouth, pharynx or upper part of the larynx creates tissue volume loss or nerve deficit that sometimes the remaining tissue can’t compensate for, resulting in dysphagia. The bigger the cancer, the bigger the deficit and the more the dysphagia.
Radiation in the early phase of treatment can cause dry mouth and difficulty creating a bolus. If mucositis (inflammation of mouth and throat lining) is present, it can be painful to swallow. Long term, the biggest problem with radiation is the scarring of the tongue and throat muscles making swallowing difficult.
Swallowing management begins by thinking about swallowing before cancer treatment begins and problems arise. A multi-disciplinary team discussion should identify the at-risk individuals based on where the cancer started, what their current swallowing status is, what the current weight loss is and what the expected treatment is going to be.
We recommend early referral of high-risk individuals before treatment to a swallow therapist to assess swallowing and implement therapy for when it gets difficult.
The decision for feeding via nasogastric (nose to stomach) or gastrostomy (hole in the stomach) tubes can be a difficult one. It’s important to encourage swallowing during treatment because it becomes more difficult to swallow after treatment if one hasn’t been doing so for a while.
We don’t want people to get inadequate nutrition if they can’t cope, resulting in a loss of immunity and physical resilience, so continuous monitoring of weight and swallow ability is necessary. The swallow team are invaluable in this regard. If surgical intervention with a feeding gastrostomy is necessary, it needs to be done without interrupting the patient’s cancer care.
Feeding tubes are essential when the swallowing becomes unsafe and food or liquids enter the airway. Aspiration pneumonia can be life-threatening and must be avoided.
A multi-disciplinary team approach is essential to achieve the best curative outcomes for patients, but the biggest advances have come from decreasing suffering and restoring quality of life. Good swallowing is critical for good quality of life.
MEET THE EXPERT – Dr Mark Torres-Holmes
Dr Mark Torres-Holmes is an ENT and head and neck surgeon, and he is concerned about the global rise in cancers of the throat or oropharynx.