Abstract
BACKGROUND: The M. D. Anderson Symptom Inventory (MDASI) is a psychometrically validated patient-reported outcome measurement that assesses the severity and impact of multiple symptoms related to cancer and its treatment. With the MDASI, patients rate 13 common "core" symptoms and 6 items that reflect symptom interference with functioning. Several MDASI modules (core symptom and interference items plus additional symptoms specific to a particular cancer type or treatment modality) have been developed. Although the original MDASI validation study encompassed various cancer types, the instrument's psychometric properties have not been examined in a homogenous sample of patients with breast cancer in a national multicenter study. MATERIALS AND METHODS: We performed a secondary analysis of data from an Eastern Cooperative Oncology Group study to establish the reliability, validity, and sensitivity of the MDASI in a large sample of patients with breast cancer (n = 1544), 78% of whom were receiving treatment. The instrument was administered twice, approximately 1 month apart. RESULTS: Internal consistency and test-retest reliability were adequate, with Cronbach α values ≥ 0.85 and intraclass correlations ≥ 0.76 for all subscales. Known-group validity was evaluated by using performance status, tumor response, and disease stage. Sensitivity to change in patient-reported quality of life was established. CONCLUSION: The MDASI is a valid, reliable, and sensitive symptom-assessment instrument that can enhance descriptive and clinical studies of symptom status in patients with breast cancer. Future studies might include cognitive debriefing and qualitative interviews to identify additional disease-specific items for inclusion in a MDASI breast cancer module.