Radiation-Associated Internal Lymphoedema and Swallowing Impairment in Head and Neck Cancer: Insights From Imaging and Manometry.

INTRODUCTION Lymphoedema is a significant complication following head and neck cancer (HNC) treatment. We examined the use of computed tomography (CT) to detect internal lymphoedema (IL) based on serial assessments of volumes of swallowing structures before, during, and after radiation treatment. Volume changes were correlated with videomanometry and Functional Lumen Imaging Probe (EndoFLIP) findings to determine whether these assessments might provide insights into the impact of lymphoedema on swallowing dysfunction.

METHOD Data were collected retrospectively from 26 HNC patients who completed manometry, EndoFLIP and Sydney Swallow Questionnaire (SSQ) 12 months after radiotherapy. Seven swallowing structures were contoured on the CT simulation, the last cone-beam CT and the three-month PET/CT scan. Changes in the dimensions of swallowing structures were correlated with swallowing outcomes via linear regression models.

RESULTS There was persistent swelling in three of the seven structures three months post-radiation, compared with baseline. These were the epiglottis (0.77cm3, 95% CI [0.50, 1.04], p < 0.0001), base of tongue (6.92 cm3, [4.82, 9.03], p = 0.0001) and middle pharyngeal constrictors (2.77cm3, [1.63, 3.91], p = 0.0001). Total volume of all structures at three months was positively associated with SSQ scores (β = 31.198, [12.521, 49.875], p = 0.005). There was no significant association between the volume of swallowing structures and manometry or EndoFLIP measures.

CONCLUSION CT is a potentially valuable tool for evaluating IL in HNC patients following radiotherapy. IL of all swallowing structures was associated with worse self-reported dysphagia based on SSQ scores. These exploratory findings highlight the need for validation in a prospective study with a larger sample size.