LARYNGEAL MOVEMENT IN THE ERA OF PRECISION RADIATION THERAPY IN LARYNGEAL CARCINOMA

Abstract

Objective

To report laryngeal movement during simulation for radiation treatment planning in patients with laryngeal carcinoma.

Methods and Materials

A retrospective review of patients diagnosed with laryngeal carcinoma treated with radiation therapy was done. Movement of the larynx in cephalo-caudal direction was noted with help of fluoroscopic images taken during resting and deglutition phases. Information of variables such as patients' age, gender, tracheostomy status, stage of disease and sub-site of disease were recorded. Simple linear regression was used to assess the linear relationship between laryngeal movement and different variables.

Results

A total of 47 patients were identified between February 2006 and December 2017 whose laryngeal movement was documented during simulation. About half of the patients had stage I disease (n = 22 [46.8%]). In majority of the patients, the disease originated in glottis (n = 37 [78.7%]). The mean laryngeal movement was noted to be 0.96 cm (SD of 0.392, range: 0.5-2.0cm). There was no linear association observed between laryngeal movement and age (p = 0.239), gender (p = 0.369), tracheostomy status (p = 0.664), stage of disease (p = 0.322) or sub-site of disease (p = 0.761).

Conclusion

In this era of precision, recording laryngeal movement and incorporating in contouring remains important because it can lead to geometrical miss of target volume during radiation delivery. Our study shows a physiological motion of nearly 1 cm in a cephalo-caudal direction. We conclude that a cautious margin of planning target volume (PTV) should be considered and incorporated during radiation planning of laryngeal cancers