This is an observational cohort study aimed at investigating changes in hippocampal function and its impact on cognitive function in newly diagnosed nasopharyngeal carcinoma patients without metastasis, from baseline to a period after radiotherapy.

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.

Untreated newly diagnosed nasopharyngeal carcinoma patients without metastasis.