Prospective evaluation of the reliability, validity, and minimally important difference of the functional assessment of cancer therapy-gastric (FACT-Ga) quality-of-life instrument
Garland, Sheila N.; Pelletier, Guy; Lawe, Andrew; Biagioni, Bradly J.; Easaw, Jay; Eliasziw, Michael; Cella, David; Bathe, Oliver F.
BACKGROUND: Recently, the Functional Assessment of Cancer Therapy-Gastric (FACT-Ga) was developed to measure the quality of life (QoL) of patients with gastric cancer. This newly developed instrument has not yet been validated. METHODS: Eighty-two patients with gastric adenocarcinoma completed questionnaires at baseline. The FACT-Ga scores were measured as a function of disease stage and performance status, and they were correlated with the Medical Outcomes Study 36-item short-form health survey (SF-36), the Beck Depression Inventory-II, the Marlow-Crowne Social Desirability Scale, the Paulhus Deception Scale, and the State-Trait Anxiety Inventory. Patients received a second questionnaire 2 weeks after baseline to evaluate test-retest reliability and again at 3 months to evaluate the sensitivity of the FACT-Ga to changes in performance status and to estimate the minimally important differences in scores that represented meaningful change. RESULTS: The internal and test-retest reliability of the FACT-Ga instrument was adequate. With the exception of the social well being subscale, all FACT-Ga scores were correlated as hypothesized with other measures. Relevant components of the FACT-Ga were sensitive to changes in performance status. CONCLUSIONS: The current results indicated that the FACT-Ga provides a valid and reliable measurement of QoL in patients with gastric adenocarcinoma. It is a useful instrument for QoL assessment in clinical trials, and it also may be useful for the detection of significant changes in the QoL of individual patients. Copyright Copyright 2010 American Cancer Society.