Changes of parotid and submandibular glands caused by radiotherapy—an ultrasound evaluation

Abstract

Objective: Radiotherapy may alter the normal morphology of salivary glands located in the radiation field. These changes could be evaluated safely by sonography; however, there have been few studies in this regard. This study is aimed at evaluating the sonographic changes of the parotid and submandibular glands in patients undergoing radiotherapy for head and neck malignancies. Methods: 20 patients (16 males and 4 females) with head and neck malignancies who had been referred for radiotherapy to the Qaem Hospital in Mashhad, Iran, entered the study. Length, height, depth, echotexture, echogenicity and margins of parotid and submandibular glands were evaluated in three stages (I, before radiotherapy; II, 2 weeks after radiotherapy; and III, 6-7 weeks after radiotherapy) using sonography. Peak systolic velocity (PSV), end diastolic velocity (EDV) and resistive index (RI) were also evaluated by Doppler sonography. Results: Significant differences in length, height and depth (p 5 0.000, p 5 0.000, and p 5 0.39, respectively) and also echotexture, echogenicity and gland margins (p 5 0.000) were observed before and after radiotherapy. Doppler sonography results showed no significant differences regarding PSV, EDV and RI between sonographic stages. Echotexture and echogenicity were the only independent parameters that showed significant differences in sonographic stages I and II (p 5 0.000). Length in stage I and II (p 5 0.000) and echogenicity in stage III (p 5 0.038) were the only parameters that showed significant differences between the two glands. Conclusion: Radiotherapy may change the echotexture, echogenicity and margins of the salivary glands from homogenic to heterogenic, hyperechoic to hypoechoic and regular to irregular, respectively, and may reduce their size.

Ultrasonographic Features of the Major Salivary Glands after Radioactive Iodine Ablation in Patients with Papillary Thyroid Carcinoma

“…These features are similar to post-radiotherapy changes in the MSGs (Imanimoghaddam et al 2012;Ying et al 2007) and can be observed in senile MSGs. In addition, no patient exhibited regression of these changes on further follow-up.…”

“…Ultrasonography (US) is the primary imaging modality for pre-and post-operative assessment in PTC patients (Ahuja et al 1995;Kim DW et al 2013;Kim E et al 2008;Kim EK et al 2002). Previous studies (Imanimoghaddam et al 2012;Ying et al 2007) have reported that radiotherapy may change the echotexture, echogenicity and margins of the major salivary glands and may reduce glandular size. To the best of my knowledge, however, no previous study has reported the ultrasonographic features of the MSGs after RIA in PTC patients.…”

Diagnostic Accuracy of Ultrasonic Histogram Features to Evaluate Radiation Toxicity of the Parotid Glands

“…The ultrasound studies that have demonstrated changes in the sonographic appearance of parotid glands exposed to radiation are mostly qualitative, or at best, semiquantitative (23,24). In addition, previous studies were either on acute toxicity (24) or late toxicity (23).…”

Acoustic Radiation Force Impulse quantitative elastography: a new noninvasive technique for the evaluation of parotid glands. A preliminary study in controls and in patients with irradiated nasopharyngeal carcinoma.

“…Xerostomia is one of the most important oral complications of radiotherapy received for the head and neck malignancies and occurs as a result of the damage brought by irradiation of the salivary parenchyma [5,6]. The reduced flow and viscosity of the saliva is a direct result of the damage brought to the radiation sensitive glandular parenchyma and its subsequent reduced salivary gland function [6]. Studies have shown that there are definite links between the exposure of the glands to radiation and the subsequent size reduction [6] and change in the blood flow of the parotid glands [7].…”

“…The reduced flow and viscosity of the saliva is a direct result of the damage brought to the radiation sensitive glandular parenchyma and its subsequent reduced salivary gland function [6]. Studies have shown that there are definite links between the exposure of the glands to radiation and the subsequent size reduction [6] and change in the blood flow of the parotid glands [7]. The parotid gland (PG) function was found to be dose dependent [7,8]; the threshold beyond which the damage to the glandular parenchyma becomes prominent may lay around 30-40 Gy [4].…”