Tai Chi for Cancer-Related Fatigue During Radiotherapy in Patients With Head and Neck Cancer

Inclusion Criteria: * Histologically confirmed primary malignant tumor of the head and neck and planned to receive radiotherapy. * Age 18 to 80 years. * No regular exercise during the previous 3 months, defined as less than 150 minutes per week of moderate-intensity exercise and less than 75 minutes per week of vigorous-intensity exercise. * Eastern Cooperative Oncology Group (ECOG) performance status of 0-1. * Able to complete the baseline assessment before the start of radiotherapy. * Provides written informed consent and is willing to comply with the supervised exercise program. Exclusion Criteria: * Absolute contraindications to exercise, such as uncontrolled heart failure, severe arrhythmia, acute myocardial infarction, unstable angina, or severe aortic stenosis. * Severe musculoskeletal disease, neurological disease, or other physical disease that prevents completion of the prescribed exercise movements. * Uncontrolled brain metastases or severe bone metastases associated with a high risk of pathological fracture. * Severe cognitive impairment or psychiatric disorder, such as severe depression or schizophrenia, that prevents compliance with study instructions. * Pregnancy or breastfeeding. * Other conditions that may substantially confound fatigue assessment, including severe anemia (hemoglobin \<9.0 g/dL); hypothyroidism with thyroid-stimulating hormone (TSH) \>5 mIU/L accompanied by clinical symptoms; hyperthyroidism with TSH \<0.3 mIU/L without stable treatment; Insomnia Severity Index (ISI) score ≥15 with symptoms remaining unstable despite routine sleep management; or pain with a Numeric Rating Scale (NRS) score ≥4 that remains uncontrolled despite optimized analgesic management or requires escalation of treatment. * Participation in another structured exercise rehabilitation program or interventional study that may substantially affect the study outcomes.