Contribution of submandibular gland and swallowing structure sparing to post-radiation therapy PEG dependence in oropharynx cancer patients treated with split-neck IMRT technique

摘要

Background Radiation therapy-related dysphagia is worsened by xerostomia. The submandibular glands (SMG) produce saliva rich in lubricating mucins, and sparing the SMG has been shown to reduce xerostomia. The goal of this study was to determine whether SMG sparing IMRT is associated with reduced post-treatment PEG dependence in locally advanced oropharynx cancer patients. Methods Patients treated with definitive radiation therapy for oropharynx cancer were included in this retrospective study. Those with disease recurrence were excluded. Salivary glands and swallowing-related organs at risk, including pharyngeal constrictors, were contoured. Primary endpoint was time from end of radiation treatment to freedom from gastrostomy (PEG) tube dependence. Cox proportional hazards regression and logistic regression were used to assess influence of normal tissue doses on swallowing related endpoints. Results Sixty-nine patients were included. All had stage III/IV disease and 97% received concurrent systemic therapy. Fifty-seven percent had contralateral SMG (cSMG) mean dose ?42?Gy ( p =?0.002). Conclusions Patients treated with cSMG sparing radiotherapy had significantly shorter time to PEG tube removal after treatment, suggesting a clinically meaningful reduction in subacute dysphagia compared to non-cSMG sparing treatment.