Changes in parotid gland morphology and function in patients treated with intensity-modulated radiotherapy for nasopharyngeal and oropharyngeal tumors

Abstract

ObjectiveTo evaluate the morphological changes of the parotid glands in patients treated with intensity-modulated radiotherapy (IMRT) for nasopharyngeal and oropharyngeal tumors and the correlations with parotid function.MethodsTen patients with nasopharyngeal and oropharyngeal tumors treated with IMRT between May 2009 and January 2010 at Hokkaido University Hospital were included in this study. In the morphological assessment of the parotid glands, the sizes and computed tomography (CT) numbers of the bilateral parotid glands before and after IMRT with CT were calculated. For functional assessment of the parotid glands, we conducted the Saxon test and used a visual analog scale (VAS) for xerostomia evaluation.ResultsReductions in saliva secretion were observed in the patients treated with IMRT for nasopharyngeal and oropharyngeal tumors, and there was a significant correlation between the reduction in saliva secretion and the VAS. The reductions in the parotid gland size and CT number were larger on the ipsilateral side than on the contralateral side. The reduction in saliva secretion was not significantly correlated with the reduction in parotid gland size, but was significantly correlated with the reduction in CT number.ConclusionsMorphological and functional changes of the parotid glands were observed after IMRT for nasopharyngeal and oropharyngeal tumors, and preservation of the contralateral parotid glands was only partly achieved. Among the morphological changes of the parotid glands, the CT number may be considered a predictor of parotid function after radiotherapy.

Structural Variations in Parotid Glands Induced by Radiation Therapy in Patients with Oral Carcinoma Observed on Contrast-Enhanced Computed Tomography

“…Scalco et al [ 15 ] analyzed the usefulness of texture analysis for the assessment of structural changes in the parotid glands induced by radiotherapy that can be seen on CT. Marzi et al [ 16 ] reported that early changes in irradiated major salivary glands can be noninvasively evaluated by intravoxel incoherent motion MRI. In recent years, density variation of parotid glands during IMRT for head and neck cancer [ 17 , 18 ] and radiation-induced CT density changes in the parotid glands [ 19 , 20 ] have been reported in the literature. The authors consider that the relation between multimodal imaging, such as CT, MRI ultrasonography, and xerostomia could be important for subsequent research.…”

Ultrasound Elastography in Diffuse and Focal Parotid Gland Lesions

“…Initially, oedema and acute inflammation of the parotid gland appear, which are followed by fibrosis and gland hypotrophy [32] . Glandular loss of function and damage begin around 30-40 Gy [33] . In a preliminary study, Badea et al [34] verified variation in shear wave velocities between healthy and irradiated glandular parenchyma.…”

Two-stage autotransplantation of the human submandibular gland: First long-term results

“…It has been reported that intensity‐modulated radiotherapy (IMRT) reduces damage to the salivary glands and is superior to conventional radiotherapy, and should thus be considered as the standard treatment in patients with head and neck cancer . However, the general clinical experience is that patients still have a variety of subjective complaints, because the parotid glands are spared only to some extent . It is well known that more than two‐thirds of the saliva production is done by the submandibular glands .…”