-Original-

Cross-cultural Validation of the Japanese Version of the Lung Cancer Subscale on the Functional Assessment of Cancer Therapy-Lung

Erika Saitoh^1,2, Yuki Yokomizo¹, Chih-Hung Chang³, Sonya Eremenco⁴, Hiyori Kaneko^5,6 and Kunihiko Kobayashi^1,5,6

¹Department of Respiratory Medicine, Saitama Medical University
²Department of Respiratory Medicine, Komagome Hospital, Tokyo
³Buehler Center on Aging, Health and Society, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
⁴Center on Outcomes, Research and Education, Evanston Nothwestern Healthcare, Evanston, Illinois, USA
⁵Department of Pulmonary Medicine/Infection and Oncology, Graduate School of Medicine, Nippon Medical School
⁶East Japan Chesters Group, Tokyo

Background: The Functional Assessment of Cancer Therapy-Lung (FACT-L) questionnaire, which consists of a core questionnaire (the General Measure of FACT [FACT-G]) and a 9-item Additional Concerns comprised of a 7-item Lung Cancer Subscale (LCS), was developed in an English-speaking culture. The validation of the Japanese FACT-G was reported previously, and this report describes the cross-cultural validation of the LCS.
Methods: The Japanese version of the LCS was developed through an iterative forward-backward translation sequence used throughout the FACT Multilingual Translation Project. In evaluating psychometric performance, its construct validity was investigated with Cronbach's alpha coefficient and factor analysis. Clinical validities of a known-groups comparison and longitudinal validity were also investigated.
Results: The FACT-L was administered twice to 180 patients with lung cancer within 2 weeks. The Japanese LCS had borderline values for Cronbach's alpha coefficients (0.62-0.67). Factor analysis indicated that the LCS had the three dimensions of respiratory symptoms, appetite plus body weight, and clear thinking. For clinical validity, a known-groups comparison showed that the LCS could differentiate patients according to truth disclosure, as Japanese doctors sometimes do not fully inform terminally ill patients. However, responsiveness was not proved when performance status was used as an anchor, probably owing to the short interval between the administration of the two measures.
Conclusion: The Japanese version of the LCS asked questions about multiple symptoms of patients with lung cancer, as did the original English LCS. The longitudinal clinical validity of the Japanese version should be investigated in future clinical trials.

J Nippon Med Sch 2007; 74: 402-408

Keywords
cross-cultural comparison, Japanese, lung carcinoma, quality of life, questionnaire, Functional Assessment of Cancer Therapy-Lung, Lung Cancer Subscale

Correspondence to
Kunihiko Kobayashi, MD, PhD, Department of Respiratory Medicine, Saitama Medical University, 38 Morohongo, Moroyama Iruma, Saitama 350-0495, Japan
kobakuni@saitama-med.ac.jp

Received, April 17, 2007
Accepted, September 18, 2007