Dose to swallowing structures and dysphagia in head and neck Intensity Modulated Radiation Therapy - A long term prospective analysis.

Abstract

To analyse the long term swallowing function in head and neck cancer patients and correlate with the dose to midline swallowing structures. The use of concurrent chemo radiation (CRT) as the present standard of care resulted in high rates of early and late toxicities. Dysphagia, aspiration, and xerostomia are early as well as late effects of radiation. Not many studies on the dysphagia scores during radiation and follow-up period have correlated dose to the swallowing structures, hence this study. Histologically proven head and neck cancer patients treated with intensity modulated radiation therapy were accrued in this study. The pharyngeal constrictors, larynx and cervical oesophagus were contoured and labelled as midline swallowing structures. The volume of the midline swallowing structures which were outside the PTV was delineated separately and was given a mean dose constraint of 45Gy. Dysphagia was assessed at baseline, weekly intervals during irradiation and follow-up at six years. The dose to the structures for swallowing was correlated with degree of dysphagia. There was a gradual increase in the dysphagia grade during the course of radiation. There was a significant recovery of late dysphagia compared to dysphagia during the completion of radiation therapy in patients who received <45Gy to the swallowing structures (p<0.0001). Giving a constraint to the swallowing structure and limiting it to <45Gy resulted in earlier recovery of swallowing function resulted in good physical, mental and social well being of the patients when compared to those who received >45Gy.