Longitudinal changes over 2 years in parotid glands of patients treated with preoperative 30-Gy irradiation for oral cancer
Source: jjco.oxfordjournals.org Authors: Etsushi Tomitaka et al. Objective: To evaluate longitudinal changes in parotid volumes and saliva production over 2 years after 30 Gy irradiation. Methods: We retrospectively evaluated 15 assessable patients treated for advanced oral cancer. Eligibility criteria were a pathologic diagnosis of squamous cell carcinoma, preoperative radiation therapy with a total dose of 30 Gy delivered in 15 fractions, and the availability of longitudinal data of morphological assessments by computed tomography and functional assessments with the Saxon test spanning 2 years after radiation therapy. In the Saxon test, saliva production was measured by weighing a folded sterile gauze pad before and after chewing; the low-normal value is 2 g/2 min. Repeated-measures analysis of variance with Bonferroni adjustment for multiple comparisons was used to determine the longitudinal changes. Results: The normalized ipsilateral parotid volumes 2 weeks and 6-, 12- and 24 months after radiation therapy were found to be 72.5, 63.7, 66.9 and 78.1%, respectively; the normalized contralateral volumes were 69.8, 64.6, 72.2 and 82.0%, respectively. The bilateral parotid volumes were significantly decreased after radiation therapy (P