Psychometric evaluation of the Taiwanese version of the functional assessment of cancer therapy: a questionnaire for patients with lung cancer

OBJECTIVE: The Functional Assessment of Cancer Therapy-Lung (FACT-L) consists of the Functional Assessment of Cancer Therapy-General (FACT-G) and the Lung Cancer Subscale. The FACT-L is commonly used to measure quality of life in patients with lung cancer. This study evaluated the reliability and validity of the FACT-L in examining patients with lung cancer in Taiwan.

DESIGN: This was a methodology study.

SETTING: Patients with lung cancer at a regional hospital in Northern Taiwan.

PARTICIPANTS: Patients who had received an early diagnosis of lung cancer between 2013 and 2015 were recruited as respondents.

INTERVENTION(S): None.

MAIN OUTCOME MEASURE(S): To verify the reliability and validity of the Taiwanese version of the FACT-L.

RESULTS: A total of 104 patients who had received an initial diagnosis of lung cancer were recruited. The overall internal consistency of the FACT-L, as assessed using Cronbach's α, was 0.82. Among the patients, 64 had a test-retest reliability (r) of 0.45 (P < 0.001) at 6 weeks after treatment. Moreover, longitudinal research indicated that the FACT-L detected score differences before and after treatment in these patients (Cohen's d = -0.26). The Taiwanese version of the FACT-L considers 2-year survival as the gold standard, and the optimal combination of sensitivity and specificity was obtained when the receiver operating characteristic curve revealed cutoff points of 80 and 68 for the FACT-L and FACT-G, respectively.

CONCLUSIONS: The Taiwanese version of the FACT-L can be widely applied to assess the quality of life of patients with lung cancer.