The effect of amifostine or IMRT to preserve the parotid function after radiotherapy of the head and neck region measured by quantitative salivary gland scintigraphy

Abstract

Purpose In this retrospective study, two approaches to preserve the parotid function after radiotherapy (RT) were compared: application of the radioprotective agent amifostine during RT and parotid-sparing intensity-modulated radiotherapy (IMRT). Patients and methods Patients were qualified for this analysis if (1) both parotid glands received a radiation dose of ⩾50 Gy using conventional radiotherapy techniques (cRT) or if they received a parotid-sparing IMRT as alternative, if (2) salivary gland scintigraphies before and after RT were performed, and if (3) a normal parotid function was present before RT. Quantitative salivary gland scintigraphy was used to assess the parotid gland function. Results Altogether 275 salivary gland scintigraphies of 100 patients were analyzed. The mean relative tracer uptake (Δ U) of patients treated with cRT, cRT with amifostine and IMRT 1–12 months after RT was 0.59 (95%CI 0.54–0.65), 0.67 (95%CI 0.59–0.76), and 0.93 (95%CI 0.78–1.07), respectively. The mean relative Δ U 13–47 months after RT was 0.40 (95%CI 0.32–0.49), 0.60 (95%CI 0.48–0.71), and 0.92 (95%CI 0.56–1.28). At 1–12 months after RT, ANOVA testing with post-hoc comparison using the Bonferroni correction showed a significant difference between IMRT and cRT ( p < 0.001) or IMRT and amifostine ( p < 0.01). The difference between amifostine and cRT was not significant during the first year. At 13–47 months after RT, the difference between cRT and amifostine was significant ( p = 0.02). Conclusion Our data suggest that both amifostine and IMRT are able to partially preserve the parotid function after radiotherapy. The effect of IMRT appeared to be much greater.