Development and psychometric evaluation of a symptom assessment scale for adjuvant radiotherapy in breast cancer patients based on the symptom experience model.

To develop and validate a symptom assessment scale for postoperative adjuvant radiotherapy in breast cancer patients based on the Symptom Experience Model, providing a basis for healthcare professionals to evaluate symptoms and formulate personalized symptom management plans. A preliminary scale was constructed using patient self-reported outcomes and the Symptom Experience Model as theoretical foundations, incorporating literature review, Delphi expert consultation, and pre-surveys. The scale was refined based on feedback. The final breast surgery postoperative adjuvant radiotherapy symptom assessment scale comprises 5 dimensions and 23 items. Exploratory factor analysis extracted 5 common factors, accounting for 63.047% of cumulative variance. Confirmatory factor analysis results indicated good model fit. The scale's content validity index was 0.903, with item-level content validity indices ranging from 0.833 to 1.000. The total Cronbach's α coefficient was 0.910, with dimension-specific Cronbach's α coefficients ranging from 0.789 to 0.887. The split-half reliability for the total scale was 0.821, with dimension-specific reliability coefficients ranging from 0.711 to 0.876. The total scale score showed a significant negative correlation with FACT-B scores (r = - 0.595, P < 0.001). The Adjuvant Radiotherapy Symptom Assessment Scale for Breast Cancer demonstrates good reliability and validity. It can guide healthcare providers in conducting more targeted assessments of patients and provide a basis for developing personalized symptom management plans.