Olfactory Change After Chemo-radiotherapy for Nasopharyngeal Carcinoma

Inclusion Criteria: * Age 18-70, regardless of sex. * Patients with newly histologically confirmed non-keratinizing nasopharyngeal carcinoma, type of WHO II or III, clinical stage III-IVa (according to the 8th American Joint Committee on Cancer \[AJCC\] edition). * ECOG (Eastern Cooperative Oncology Group) score: 0-1. * Patients receiving induction chemotherapy with concurrent chemoradiotherap. * Patients must sign informed consent and be willing, and well understood the objective and procedure of this study. Exclusion Criteria: * Women in pregnancy or lactation. * Patients who received additional treatment during the observation period due to disease progression. * Patients with significantly lower heart, liver, lung, kidney and bone marrow function. * Patient with severe medical condition. * with a condition that could cause olfactory dysfunction, such as septum deviation, nasal polyposis, nasopharyngeal necrosis, congenital olfactory dysfunction, septum surgery, head trauma, chronic rhinosinusitis, allergic rhinitis, or psychiatric or neurological disorders, such as Parkinson's, MS and Alzheimer's disease, or long history of psychiatric drug, corticosteroids or other drug that may affect olfactory function. * Not able to return for evaluation of olfactory function or follow-up (language, practical implementation, mental condition)