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.