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Radiation Trismus — SCE Medical Oncology MCQ

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ModerateHead & Neck CancerRadiation TrismusSCE Medical Oncology

A 58-year-old man with head and neck SCC post-chemoradiotherapy develops severe trismus (maximum inter-incisal opening 15 mm). He cannot open his mouth adequately for dental care or nutrition. What is the cause and management?

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Correct answer: D — Radiation-induced fibrosis of the pterygoid and masseter muscles — management includes jaw-stretching exercises (TheraBite/Dynasplint devices), physiotherapy and prevention with regular jaw exercises starting during radiotherapy

Radiation-induced trismus affects approximately 25-45% of patients after H&N RT involving the pterygoid muscles and TMJ. It results from fibrosis of masticatory muscles and is progressive without intervention. Prevention is key: jaw-stretching exercises should begin DURING radiotherapy and continue for life. Treatment: TheraBite device (progressive passive jaw stretching), physiotherapy, botox injections for spasm, and pentoxifylline + vitamin E (PENTOCLO — anti-fibrotic effect). Severe trismus (<20 mm opening) significantly impacts nutrition, dental care and quality of life.

Reference: NICE NG36; ESMO H&N Survivorship; Pauli et al Acta Oncol 2019