How can radiation therapy for head and neck cancer contribute to dysphagia?

• A. By causing fibrosis and reduced mobility of swallowing muscles
• B. By improving mucosal healing of the esophagus
• C. By increasing saliva production
• D. By decreasing the risk of aspiration

Answer: (A)

Radiation to the head and neck often causes fibrosis and scarring in the swallowing muscles and surrounding tissues. This stiffening affects the pharyngeal constrictors, base of tongue, and laryngeal structures, reducing their mobility and coordination during a swallow. When hyolaryngeal elevation and pharyngeal propulsion are impaired, bolus transit becomes inefficient, leaving residue and increasing the risk of penetration or aspiration. This long-term tissue change is a common way radiation contributes to dysphagia after treatment.

In contrast, radiation typically dries the mouth (xerostomia) rather than increasing saliva, does not improve mucosal healing—and can worsen mucosal injury—so those options don’t explain why radiation leads to dysphagia. And while reducing aspiration would help, radiation more often raises aspiration risk due to impaired swallow mechanics, not decrease it.