Modeling of salivary production recovery after radiotherapy using mixed models: determination of optimal dose constraint for IMRT planning and construction of convenient tools to predict salivary function.

摘要

PURPOSE: The mathematical relationship between the dose to the parotid glands and salivary gland production needs to be elucidated. This study, which included data from patients included in a French prospective study assessing the benefit of intensity-modulated radiotherapy (RT), sought to elaborate a convenient and original model of salivary recovery. METHODS AND MATERIALS: Between January 2001 and December 2004, 44 patients were included (35 with oropharyngeal and 9 with nasopharyngeal cancer). Of the 44 patients, 24 were treated with intensity-modulated RT, 17 with three-dimensional conformal RT, and 2 with two-dimensional RT. Stimulated salivary production was collected for 40 Gy. CONCLUSION: The results of this study show that the recommendation of a dose constraint for intensity-modulated RT planning should be established at the volume of the contralateral parotid gland receiving >40 Gy rather than the mean dose. For complete salivary production recovery after 24 months, the volume of the contralateral parotid gland receiving >40 Gy should be <33%. Our results permitted us to establish two convenient tools to predict the saliva production recovery function according to the dose received by the contralateral parotid gland.