Purpose: The purpose of this longitudinal study was to investigate quality of life (QOL) before, during, and after the course of radiotherapy (RT) and to identify risk factors for diminished QOL in women with breast cancer.
Methods: Patients (N = 188) completed the short-form 12 (SF-12), the Karnofsky Performance Status Scale, Memorial Symptom Assessment Scale, and the Self-Administrated Comorbidity Questionnaire 1 week prior to the start of RT. To assess changes in QOL, patients also completed the SF-12 1, 2, 3, and 6 months after the baseline. A random-intercept and slope model (mixed model) for each patient was used to estimate linear trends for the mental component score and physical component score of QOL (five time points for each patient). Descriptive statistics were used to analyze demographic and clinical characteristics.
Results: The physical component score (PCS) did not change significantly (p = 0.078) during the course of RT in women with breast cancer. An increase in the number of symptoms and a higher comorbidity profile was negatively related to the PCS. The mental component score (MCS) did not change from the start of RT until the 2-month assessment, but increased significantly after 2 months (p = 0.044). An increase in the number of symptoms was negatively related to the MCS.
Conclusion: The MCS and PCS of QOL remained stable at a diminished level except for the MCS which improved between 2 and 6 months after the start of RT. The total number of symptoms was the only variable that was negatively associated with both component scores (MCS and PCS) during the 6 months.