Prospective swallowing outcomes after IMRT for oropharyngeal cancer: Dosimetric correlations in a population-based cohort

• Four critical swallowing organs at risk are identified during oropharyngeal radiotherapy.
• Mean doses to the larynx were associated with FT dependence and dietary restrictions.
• New radiotherapy planning dose constraints are proposed.

ObjectivesTo identify dose constraints to preserve swallowing after head and neck (H&N) radiotherapy using prospectively collected functional outcomes.Materials and methodsStage III–IV oropharyngeal cancer patients were prospectively evaluated using the Royal Brisbane Hospital Outcome Measure for Swallowing and Performance Status Scale for H&N Cancer Patients at pre-treatment and 3, 6, 12, and 24 months after intensity-modulated radiotherapy. Dosimetric parameters were correlated with swallowing function.ResultsNinety-six patients were evaluated with median follow-up of 14.1 months (interquartile range 9.9–26.3). Six patients (8.3%) remained feeding tube (FT) dependent at 12 months. At 2 years, 32.6% tolerated a normal diet without restrictions. Mean doses of 55 Gy to supraglottic larynx, 44 Gy to glottic larynx, 48 Gy to cricopharyngeus, and 44 Gy to esophageal inlet were associated with >25% risk of FT dependence at 6 months.ConclusionHigher mean doses to the larynx and pharyngo-esophageal junction were associated with longer duration of FT dependence and dietary restrictions.