Treatment with Intensity Modulated Radiotherapy on the Change of Cognitive Function in Nasopharyngeal Carcinoma Patients: a Prospective Cohort Study

Inclusion Criteria: * Newly diagnosed nasopharyngeal carcinoma patients confirmed by pathology, who have not received surgical, induction chemotherapy, radiotherapy, or other anti-tumor treatments; * Clinical stage classified as AJCC 8th edition Stage I-IVa, with no distant metastasis, and who are scheduled to undergo intensity-modulated radiotherapy (IMRT) according to clinical plans; * Pathologically diagnosed as non-keratinizing nasopharyngeal carcinoma (differentiated or undifferentiated type, i.e., WHO type II or III); * All participants are Han Chinese and right-handed; * Age between 18 and 60 years, with an education level of junior high school or above; * No history of neurological diseases or head trauma; * No other severe systemic diseases other than nasopharyngeal carcinoma; * No hippocampal invasion before treatment; * Routine MRI before treatment shows no abnormal lesions in the hippocampus; * No family history of mental illness. Exclusion Criteria: * Routine MRI before treatment shows abnormal lesions in the hippocampus; * Contraindications for magnetic resonance examination; * Concurrent other brain diseases; * Pathologically diagnosed as keratinizing squamous cell carcinoma (WHO type I); * Patients with recurrence or distant metastasis; * Patients who have previously undergone radiotherapy or chemotherapy; * Abnormal function of vital organs such as heart, brain, or lungs; * History of head trauma or mental/neuro diseases; * Age less than 18 years or greater than 60 years; * Patients whose initial treatment plan is changed during the observation * period due to disease progression (including residual tumors after * radiotherapy, tumor recurrence, or newly developed distant metastasis); * Patients with diabetes or hypertension; * Those unable to cooperate in completing neurocognitive scale testing; * Those with other uncontrolled severe diseases.