Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/88901
Title: Early radiation induced changes in salivary glands in nasopharyngeal cancer patients after IMRT
Authors: Wu, WV 
Ying, MT 
Kwong, DL
Wong, GK
Khong, P
Issue Date: Apr-2019
Source: Radiotherapy and oncology, 2019, v. 133, suppl. 1 , EP-1168, p. S646 (Meeting Abstract)
Abstract: Purpose or Objective Parotid and submandibular glands are the main source of saliva. Both glands are irradiated to high dose by radical external beam radiotherapy (EBRT) in nasopharyngeal cancer (NPC) patients. Xerostomia is one of the common radiation induced complications in NPC patients caused by damaged of parotid and submandibular glands after RT.Persistent xerostomia causes difficulties in mastication and swallowing and enhances the risks of dental problems. The aims of this study were to assess the changes of the salivary glands after 6 months of post-RT using magnetic resonance imaging (MRI), ultrasonography (US), saliva flow rate and contents.
Material and Methods 25 NPC patients with stage I to III (UICC) treated by routine EBRT using 6 MV 9-field intensity modulated radiotherapy and with no previous history of salivary glands disorder were recruited. Each subject underwent US and MRI examinations, saliva test before the start of radiotherapy (RT) and at 6 months after RT. The US assessment was conducted by the same operator in which the haemodynamics including the blood flow velocity and vascular resistance of the salivary glands were measured. The MRI, which was performed using T1 and T2 axial and sagittal scans with slice thickness of 3 mm, provided the salivary glands’ morphological information. The saliva test included the measurement of mean saliva flow rate (SFR) and the main contents of the saliva including alphaamylase and immunoglobulin A (IgA). The mean values of each measured parameters were calculated and paired ttest was conducted to assess their differences between the two time intervals.
Results The mean volumes of parotid and submandibular glands were significantly reduced by about 30% at 6- month after RT (p <0.001). The two glands also demonstrated lower vascular velocity, resistive and pulsatility indices (p <0.05) when compared to the pre-RT condition. This indicated that the blood flow in the post-RT glands was slower and the blood vessels experienced lower pressure than those of the post-RT. In addition, the post-RT mean SFR was reduced by more than 9 times when compared with that in pre-RT (p < 0.001). The levels of the salivary alpha amylase and IgA were also significantly reduced at the 6-month post-RT interval.
Conclusion Our study demonstrated that there were substantive impacts on the physiological and morphological aspects of the salivary glands after radical EBRT in NPC patients. The side effects were relatively early in which most measured parameters demonstrated significant changes at 6-month post-RT interval.
Publisher: Elsevier
Journal: Radiotherapy and oncology 
ISSN: 0167-8140
DOI: 10.1016/S0167-8140(19)31588-9
Description: 38th Annual Meeting of the European-Society-for-Radiotherapy-and-Oncology (ESTRO), Apr 26-30, 2019, Milan, ITALY
Rights: Under a Creative Commons license. Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) (https://creativecommons.org/licenses/by-nc-nd/4.0/)
The following publication Wu, W. V., Ying, M. T., Kwong, D. L., Wong, G. K., & Khong, P. (2019). Early radiation induced changes in salivary glands in nasopharyngeal cancer patients after IMRT. Radiotherapy and Oncology, 133, EP-1168, S646 is available at https://dx.doi.org/10.1016/S0167-8140(19)31588-9
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