Background: The Functional Assessment of Cancer Therapy-Anemia (FACT-An) questionnaire, which consists of a core questionnaire named the General Measure of the Functional Assessment of Cancer Therapy (FACT-G) and the Anemia additional concerns subscale, was developed in an English-speaking culture. The validation of the Japanese FACT-G was reported previously (Fumimoto et al., 2001), and, in this report, a cross-cultural validation for the subscale was performed.
Methods: The Japanese version was developed through an iterative forward-backward translation sequence used throughout the Functional Assessment of Chronic Illness Therapy (FACIT) Multilingual Translation Project. In evaluating psychometric performance, its construct validity was investigated by exploratory factor-analyses, and confirmed by Cronbach's alpha coefficient.
Results: The FACT-An was given to 180 patients with lung cancer. Using the 20 items of the Anemia subscale, a factor analysis extracted four factors of fatigue, chest condition, activities and headache. When analyzed as two extracted factors, fatigue, chest condition and headache were combined to be a major factor, although the minor factor of activities still remained. Thirteen of the 20 items construct the Fatigue additional concerns subscale. Cronbach's alpha coefficients for the Fatigue subscale (0.93) and the Anemia subscale (0.88) confirmed that, although these subscales had items that focus on different aspects of anemia or fatigue, each subscale was unidimensional. Clinical validity was indicated by moderate values of Spearman's correlation coefficients between Eastern Cooperative Oncology Group performance status rating (ECOG PSR) and the Anemia subscale (-0.50) or the Fatigue subscale (-0.48).
Conclusion: Both the Fatigue subscale and the Anemia subscale are valid in Japan, indicating that FACT-An is an instrument that is applicable across cultures and particularly with a Japanese cancer population.