Reliability and validity of the Functional Assessment of Cancer Therapy-Breast quality-of-life instrument.

Abstract

PURPOSE This is the first published report on the validation of the Functional Assessment of Cancer Therapy-Breast (FACT-B), a 44-item self-report instrument designed to measure multidimensional quality of life (QL) in patients with breast cancer. The FACT-B consists of the FACT-General (FACT-G) plus the Breast Cancer Subscale (BCS), which complements the general scale with items specific to QL in breast cancer. The FACT-B was developed with an emphasis on patients' values and brevity and is available in nine languages. METHODS AND RESULTS Two validation samples were used for this report. The first (n = 47) was tested twice over a 2-month period to assess sensitivity to change. Significant sensitivity to change in performance status rating (PSR) was demonstrated for the FACT-B total score, the Physical Well-Being (PWB) subscale, the Functional Well-Being (FWB) subscale, and the BCS. Sensitivity to change in QL as measured by the Functional Living Index-Cancer (FLIC) was documented in the FACT-B total score, PWB, FWB, and Emotional Well-Being (EWB). Additional validity and reliability data were obtained from a larger sample (n = 295). The alpha coefficient (internal consistency) for the FACT-B total score was high (alpha = .90), with subscale alpha coefficients ranging from .63 to .86. Evidence supported test-retest reliability, as well as convergent, divergent, and known groups validity. CONCLUSION The FACT-B is appropriate for use in oncology clinical trials, as well as in clinical practice. It demonstrates ease of administration, brevity, reliability, validity, and sensitivity to change.