Swallowing After Radiotherapy for Nasopharyngeal Cancer (NPC): Long-Term Effects and How to Protect Your Swallow

In short: Radiotherapy for nasopharyngeal cancer (NPC) can affect swallowing not only during treatment but for many years afterwards. Over time, radiation can cause the muscles and tissues of the mouth and throat to stiffen (fibrosis) and can damage the nerves that control swallowing. This is called late radiation-associated dysphagia. Starting a swallowing preservation programme before radiotherapy, continuing it during and after treatment, and having regular swallowing reviews for life can help protect swallowing and catch problems early.

Why NPC radiotherapy affects swallowing in the long term

Radiotherapy for NPC targets the back of the nose, the skull base and the lymph nodes in the neck. The treatment area often includes the upper throat muscles, the soft palate, the base of the tongue and nearby nerves. Modern techniques such as IMRT reduce the dose to these structures, but some exposure is usually unavoidable.

• Fibrosis: treated muscles and soft tissues can gradually become stiff and weak. This may continue to progress for years after treatment ends.
• Nerve damage (lower cranial neuropathy): the nerves that control the throat, voice and tongue (cranial nerves IX, X and XII) can be affected, sometimes many years later. This can cause tongue weakness, a hoarse or weak voice, and poor throat squeeze.
• Dry mouth (xerostomia): reduced saliva makes chewing and moving food harder.
• Trismus: stiffness of the jaw muscles can limit mouth opening.
• Reduced throat sensation: food or drink may enter the airway without triggering a cough. This is called silent aspiration.

Because these changes can develop slowly, many NPC survivors swallow well for years and then notice problems 5, 10 or even more years after radiotherapy.

Signs to look out for

• Coughing or choking during or after meals or drinks
• A wet or gurgly voice after swallowing
• Food sticking in the throat, or needing several swallows for each mouthful
• Meals taking much longer, or avoiding certain foods
• Food or liquid coming back through the nose
• Unplanned weight loss
• Repeated chest infections or pneumonia
• Slurred speech, a weak voice or difficulty moving the tongue
• Difficulty opening the mouth

Repeated chest infections can be a sign of silent aspiration, even without obvious coughing during meals. An instrumental assessment such as FEES can show whether food or drink is entering the airway.

The swallowing preservation protocol

Swallowing preservation means looking after swallowing at every stage: before, during and after radiotherapy, and for life. The aim is to keep the swallowing muscles working, avoid long periods without eating or drinking by mouth, and pick up changes early.

Before radiotherapy

• Baseline swallowing assessment by a speech therapist, with FEES if needed, so later changes can be compared
• Education for the patient and family on how radiotherapy may affect swallowing, short and long term
• Start swallowing exercises and learn to do them correctly
• Measure mouth opening and start jaw stretches if there is a risk of trismus
• Dental review and nutrition advice as part of the cancer team’s care

During radiotherapy

• Keep eating and drinking by mouth as much as is safe, even if textures need to be softer. Muscles that are not used weaken quickly: “use it or lose it”.
• Continue swallowing exercises daily, adjusted for pain and fatigue
• Regular review by the speech therapist to adjust textures and strategies
• Good pain control and mouth care, working with the oncology team, so swallowing can continue
• If a feeding tube is needed, keep swallowing small amounts safely when advised, so the muscles stay active

In the months after radiotherapy

• Rebuild swallowing: continue exercises and gradually return to a normal diet
• Wean off the feeding tube as soon as it is safe
• Reassess swallowing, including FEES where needed, as swelling settles
• Continue jaw stretches to prevent or reduce trismus

Long term: for life

• Maintenance exercises as advised by your speech therapist, even when swallowing feels normal
• A swallowing review at least once a year, or sooner if anything changes
• Act early on new symptoms: late swallowing changes are easier to manage when caught early
• Good oral hygiene, which reduces the risk of chest infection if aspiration occurs
• Keep a healthy weight and watch for unplanned weight loss

Exercises and therapies that may help

Therapy is planned after an assessment, because the right exercises depend on which parts of swallowing are affected. Options may include:

• Chin Tuck Against Resistance (CTAR) to strengthen the muscles under the chin that help open the food pipe
• Effortful swallow, tongue strengthening and tongue-hold (Masako) exercises for throat squeeze and tongue base movement
• The Mendelsohn manoeuvre to prolong opening of the food pipe
• Jaw stretching exercises for trismus
• Expiratory muscle strength training (EMST) to strengthen coughing and airway protection
• Surface EMG (sEMG) biofeedback, which shows muscle activity on a screen to help you exercise more accurately
• Safe swallowing strategies and texture changes to reduce the risk of aspiration

About the research: the large PRO-ACTIVE trial (952 patients receiving radiotherapy for head and neck cancer) found that feeding tube use was lower than expected and swallowing outcomes were favourable in all groups that received swallowing therapy support, whether exercises were started early or later, and whether therapy was more or less intensive. Keeping patients eating, drinking and exercising with speech therapy support is the common thread.

How we can help

We provide home-based and clinic swallowing assessments, FEES, sEMG biofeedback therapy and second opinions for complex dysphagia, including long-standing swallowing difficulties many years after NPC treatment. Contact us to arrange an assessment.

Frequently asked questions

References

• Hutcheson, K.A., Lewin, J.S., Barringer, D.A., et al. (2012). Late dysphagia after radiotherapy-based treatment of head and neck cancer. Cancer, 118(23), 5793–5799.
• Patterson, J.M. (2019). Late effects of organ preservation treatment on swallowing and voice; presentation, assessment, and screening. Frontiers in Oncology, 9, 401. doi:10.3389/fonc.2019.00401
• Hutcheson, K.A., Fuller, C.D., Pytynia, K.B., et al. (2025). PRO-ACTIVE: Results of a pragmatic phase IV randomized trial comparing the effectiveness of prophylactic swallow intervention for patients receiving radiotherapy for head and neck cancer. Journal of Clinical Oncology, 43(17_suppl), LBA12000.
• Liu, W.S., Chien, J.C., Huang, Y.H., et al. (2022). High superior-middle pharyngeal constrictor muscle mean dose correlates with severe late lung infection and survival in nasopharyngeal cancer patients. Cancer Management and Research, 14, 1063–1073.
• Yoon, W.L., Khoo, J.K.P., & Rickard Liow, S.J. (2014). Chin Tuck Against Resistance (CTAR): New method for enhancing suprahyoid muscle activity using a Shaker-type exercise. Dysphagia, 29(2), 243–248.

Related articles: Chin Tuck Against Resistance (CTAR): A Guide from the Originator · Swallowing After Brainstem Stroke (Lateral Medullary Syndrome)

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Written by Yoon Wai Lam, Director and Senior Principal Speech Therapist, B.Speech Sc. (Hons), in clinical practice since 2001 and originator of the CTAR swallowing exercise. This article is for general information and does not replace an individual assessment. Contact us to discuss a specific case.