title: Measurement properties of the English and Chinese versions of the Functional Assessment of Cancer Therapy-Breast (FACT-B) in Asian breast cancer patients.
abstract: The objective of the study was to examine the measurement properties of and comparability between the English and Chinese versions of the Functional Assessment of Cancer Therapy-Breast (FACT-B) in breast cancer patients in Singapore. This is an observational study of 271 Singaporean breast cancer patients. The known-group validity of FACT-B total score and Trial Outcome Index (TOI) were assessed in relation to performance status, evidence of disease, and treatment status cross-sectionally; responsiveness to change was assessed in relation to change in performance status longitudinally. Internal consistency and test-retest reliability were evaluated by the Cronbach's alpha and intraclass correlation coefficient (ICC), respectively. Multiple regression analyses were performed to compare the scores on the two language versions, adjusting for covariates. The FACT-B total score and TOI demonstrated known-group validity in differentiating patients with different clinical status. They showed high internal consistency and test-retest reliability, with Cronbach's alpha ranging from 0.87 to 0.91 and ICC ranging from 0.82 to 0.89. The English version was responsive to the change in performance status. The Chinese version was shown to be responsive to decline in performance status but the sample size of Chinese-speaking patients who improved in performance status was too small (N = 6) for conclusive analysis about responsiveness to improvement. Two items concerning sexuality had a high item non-response rate (50.2 and 14.4%). No practically significant difference was found in the total score and TOI between the two language versions despite minor differences in two of the 37 items. The English and Chinese versions of the FACT-B are valid, responsive, and reliable instruments in assessing health-related quality of life in breast cancer patients in Singapore. Data collected from the English and Chinese versions can be pooled and either version could be used for bilingual patients.
authors.affiliation: Department of Medical Oncology, National Cancer Center, Singapore, Singapore.
authors.forename: Raymond
authors.initials: R
authors.lastname: Ng
authors.forename: Chun Fan
authors.initials: CF
authors.lastname: Lee
authors.forename: Nan Soon
authors.initials: NS
authors.lastname: Wong
authors.forename: Nan
authors.initials: N
authors.lastname: Luo
authors.forename: Yoon Sim
authors.initials: YS
authors.lastname: Yap
authors.forename: Soo Kien
authors.initials: SK
authors.lastname: Lo
authors.forename: Whay Kuang
authors.initials: WK
authors.lastname: Chia
authors.forename: Alethea
authors.initials: A
authors.lastname: Yee
authors.forename: Lalit
authors.initials: L
authors.lastname: Krishna
authors.forename: Cynthia
authors.initials: C
authors.lastname: Goh
authors.forename: Yin Bun
authors.initials: YB
authors.lastname: Cheung
mesh_terms: D000328:Adult; D044466:Asian People / Q000523:psychology / Q000706:statistics & numerical data; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000523:psychology / Q000628:therapy; D005260:Female; D006801:Humans; D007802:Language; D008875:Middle Aged; D011788:Quality of Life; D015203:Reproducibility of Results; D012846:Singapore / Q000453:epidemiology / Q000208:ethnology; D011795:Surveys and Questionnaires