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

Abstract

SummaryBackgroundXerostomia is one of the commonest radiation-induced complications in patients with head and neck carcinoma. The aim of this study was to assess structural variations in parotid glands induced by radiation therapy in patients with oral carcinoma with contras-enhanced computed tomography (CECT).Material/MethodsA retrospective study was performed in 41 patients with oral carcinoma who underwent CECT for head and neck malignancies before and after radiotherapy. We analyzed the relationship between parotid density variations, parotid volume change, as seen on CECT, and the mean radiation dose applied to the parotid glands in patients with oral carcinoma immediately after radiotherapy, and 2 and 3 years later.ResultsImmediately after radiotherapy, high-density changes on contrast-enhanced CT were observed in 70.5% of the irradiated parotids. Low-density changes due to fat degeneration were seen in 46.2% and 72.2% of the irradiated parotids 2 and 3 years after radiotherapy, respectively. The mean dose applied to the parotids with the low-density changes and without such changes 3 years after radiotherapy was 46.0 Gy and 27.7 Gy, respectively (p=0.049). Furthermore, parotid shrinkage was observed in 63.6% of the irradiated parotids.ConclusionsThis study suggests that the structural variations in parotid glands induced by radiotherapy included high-density changes that were observed immediately after radiotherapy and low-density changes that were seen at late follow-up. This study should be useful for clinicians in the assessment of radiation-induced injuries in the parotids with respect to early prediction of xerostomia.

Morphology, Volume, and Density Characteristics of the Parotid Glands before and after Chemoradiation Therapy in Patients with Head and Neck Tumors

“…With regard to density changes, a significant variation was found in our study. In fact, increases of 30% on the right parotid gland and 24.9% on the left one (measured in HU) were observed, which corroborates the findings by Cheng et al [10], Ogura et al [11], and Wu et al [20]. However, Fiorino et al [22] and Xu et al [23] found reductions in the density of the glands.…”

“…is discrepancy can be explained by differences in the radiation dosage. Other studies [10,11] demonstrated that an increased density of salivary glands was observed with doses above 4.500 cGy, which was the case with all the patients in our study. Moreover, studies reporting a decrease in the density values point to a possible association with the gland's deformation [22].…”

“…Radiation-induced xerostomia is caused by a reduced volume of saliva secretion (gland hypofunction) or change in salivary composition, which may affect swallowing and speech, besides compromising oral health [5]. Xerostomia is the most common radiation-induced complication in HNC patients, which can significantly reduce the quality of life [10][11][12][13].…”

Structural evaluation of Parotid gland in post radiotherapy oral cancer patients: A prospective study

“…Majority of the salivary secretion is contributed by the PGs. These are the largest salivary glands and are located at the pre-auricular region (1)(2)(3)(4)(5) . It is quite unfortunate that incidence of oral cancer is on rise.…”

“…However radiotherapy leads to various side effects, it is still considered as an important treatment modality for maxillofacial carcinoma patients (1)(2)(3)(4)(5)(6)(7)(8)(9)(10) . Persistent xerostomia is one of the side effects due to radiation exposure and subsequent damage to parotid and submandibular salivary glands.…”