Quantitative assessment of salivary gland function by radioisotopic scanning in a randomized trial of Pilocarpine for prevention of radiation induced Xerostomia [Persian]

Introduction: Radioisotope scanning is the best method for objective assessment of salivary gland function. Thus, it was used in a randomized trial of concomitant pilocarpine for assessment of radiation-induced xerostomia, in addition to subjective evaluation by an approved questionnaire and objective standard xerostomia grading. Methods: Patients randomized in placebo-controlled trial of pilocarpine concurrent with irradiation for prevention of radiation-induced xerostomia were evaluated by salivary gland scintigraphy immediately before and ۶ months after the end of head and neck radiotherapy. Salivary gland function was measured by ejection fraction (EF) of Technetium-۹۹m pertechnetate. The mean values for pre and post-radiotherapy scans were calculated and compared. Also post-radiotherapy scan findings in the two groups of pilocarpine and placebo were compared using the student’s t-test. In addition, comparison was made between the scan results and the subjective findings and objective gradings. Results: Twenty patients underwent the pre-radiotherapy salivary scintigraphy, and also ۲۰ post-radiotherapy scans were performed. Mean parotid EF was ۶۰.۸۵% in the pre-radiotherapy and ۹.۰۸% in the post-radiotherapy scans (P<۰.۰۱). The means for submandibular glands in the pre and post-radiotherapy scans were ۴۱% and ۱۱.۲%, respectively (P<۰.۰۱). Also the mean EF was ۱۴.۵% in the pilocarpine group and ۳.۶۵ in the placebo group for parotid glands (P=۰.۰۷) and ۱۸.۳% and ۴.۱% respectively for submandibular glands (P<۰.۰۵). The salivary scans confirmed the subjective and objective xerostomia findings. Conclusion: Salivary gland scintigraphy is a valuable method for evaluation of xerostomia after head and neck radiotherapy, quantitatively demonstrating the protective effect of pilocarpine compared to placebo on salivary glands.