Impact of radiation dose to the swallowing organs on death from aspiration pneumonia in oral cavity cancer.

OBJECTIVES

Aspiration pneumonia is a major cause of non-cancer mortality following radiotherapy for head and neck cancer. This study aims to investigate its incidence and risk factors in patients receiving adjuvant radiotherapy for oral cavity cancer (OCC).

MATERIALS AND

METHODS

This study enrolled 1043 patients with OCC who underwent surgery and adjuvant intensity-modulated radiotherapy between 2010 and 2020 at two tertiary centers. Mean radiation dose delivered to the superior, middle, and inferior pharyngeal constrictor muscles (PCMs), cricopharyngeus muscle, and larynx were compared between patients who died from aspiration pneumonia and those who were alive or died from other causes.

RESULTS

Median follow-up was 5.4 (IQR: 2.9-8.7) years. Among patients with non-cancer mortality (n = 90), aspiration pneumonia was the cause in 56 (62.2 %) patient. The mean dose delivered to the swallowing structures was higher in patients who died of aspiration pneumonia (p < 0.05). Multivariable analysis revealed that a higher mean dose to the superior PCM and supraglottic larynx was independently associated with an increased risk of death from aspiration pneumonia (superior PCM: hazard ratio: 1.08, 95 % confidence interval: 1.02-1.13; p = 0.008; supraglottic larynx: hazard ratio: 1.10, 95 % confidence interval: 1.05-1.16; p < 0.001). On multivariable analysis with dose level stratification, a mean dose > 55 Gy to the superior PCM and 50-55 Gy or > 55 Gy to the supraglottic larynx were independently associated with an increased risk of death from aspiration pneumonia (all p < 0.05).

CONCLUSION

Higher radiation doses to the superior PCM and supraglottic larynx were associated with increased mortality from aspiration pneumonia.