The relations of dosimetric parameters with long-term outcomes and late toxicities in advanced T-stage nasopharyngeal carcinoma with IMRT

Background Balancing the dose requirements between targets and normal tissue is a challenge in radiation of nasopharyngeal carcinoma (NPC). The purpose of this study is to evaluate the dosimetric parameters and clinical outcomes in NPC. Methods We presented a retrospective review of patients with T3-4 NPC treated by intensity-modulated radiation therapy (IMRT). Patient characteristics, dosimetric parameters, and the follow-up data for survival and late toxicities were analyzed. Results The 5-year overall survival, local relapse-free survival, and distant metastasis-free survival were 83.0%, 90.1%, and 82.4%, respectively. Multivariate analysis revealed that the volume of involved lymph node was an independent prognostic factor. The volume of primary tumor and the maximal dose were significant factors affecting temporal lobe injury. Conclusions IMRT provided satisfactory local control for advanced T-stage NPC, with acceptable late toxicities. The dose constraint criteria of selected critical structures can be appropriately loosen.