Dose–volume correlates of the prevalence of patient-reported trismus in long-term survivorship after oropharyngeal IMRT: A cross-sectional dosimetric analysis

•Trismus remains a highly prevalent survivorship concern in the IMRT era.•Integration of patient-reported outcomes into predictive toxicity models is a must.•The proposed dosimetric constraints may reduce the risk of trismus in OPC patients. To ascertain the dose–toxicity relationship for the prevalence of self-reported trismus in long-term survivors after intensity-modulated radiotherapy (IMRT) for oropharyngeal carcinoma (OPC). Self-reported mouth opening was ascertained prospectively via a cross-sectional survey of OPC survivors using the intraoral finger-test. RT dose–volume histograms (DVHs) were generated for the following masticatory regions of interest: medial pterygoid, lateral pterygoid, and masseter muscles which were designated as ipsilateral or contralateral to the primary tumor. Trismus was defined as self-reported mouth opening of