Background:Simultaneous radiotherapy and chemotherapy are the core treatment for nasopharyngeal carcinoma; however, the damage caused by this treatment can seriously affect immune function and quality of life of patients. These effects may lead to treatment interruption, ultimately impacting treatment effectiveness. Methods: This retrospective study analyzed the role of thymic neoadjuvant immunotherapy in improving the immune function and quality of life in patients with nasopharyngeal carcinoma undergoing concurrent radiotherapy and chemotherapy between January and December 2023. Among 24 patients (14 men and 10 women, median age 53 years), the pathological type was non-keratinizing squamous cell carcinoma, undifferentiated, with staging ranging from T2N1 to T3N0M0 (stage II–III). All patients were administered concurrent radiochemotherapy and were randomly assigned into two groups based on whether thymus neoadjuvant therapy was administered. The experimental group included 12 patients who received thymic neoadjuvant immunotherapy during radiotherapy and chemotherapy until within 3 months of the end of the treatment. The control group comprised 12 patients who did not receive thymic neoadjuvant therapy during treatment. The radiation-induced oral mucositis, CD4+ T cell, CD8+ T cell, neutrophil count/lymphocyte count (NLR), lactate dehydrogenase (LDH), Epstein-Barr virus (EBV) DNA, and quality of life (QOL) of these patients was compared between the adjuvant treatment groups before, during, and 1 and 3 months after treatment. Results: At baseline, sex, age, pathological type, stage, NLR, LDH, EBV DNA, CD4+, CD8+, and quality of life scores did not differ significantly between the two groups before treatment. In the treatment group, during the same period of radiotherapy and chemotherapy, 12 patients with radiation-induced oral mucositis were mainly grade 1-2, and only 2 patients developed grade 3. However, all 12 patients in the control group developed grade 3-4 radiation-induced oral mucositis, which was significantly more severe than that in the treatment group. After 1 and 3 months of treatment, the CD4+ and CD8+ T cell counts were significantly higher in patients in the experimental group than those in the control group. Additionally, the experimental group also showed larger decreases in NLR, LDH, and EBV DNA compared with the control group. Moreover, the recovery of quality of life in the experimental group was significantly better than in the control group (P<0.05). Conclusion: These results demonstrated that thymic neoadjuvant immunotherapy can improve the adverse side effects of concurrent radiotherapy and chemotherapy and enhance immune function and quality of life of patients with nasopharyngeal carcinoma.