Measuring quality of life among cervical cancer survivors: preliminary assessment of instrumentation validity in a cross-cultural study

Background With growing interest in cross-cultural and multicultural cancer-related quality of life studies, the need to assess reliability and validity of quality of life measures for linguistically and culturally diverse cancer survivors is pressing. Methods Reliability and validity of the English and Spanish versions of the Functional Assessment of Cancer Therapy (FACT)-G subscales were tested with a sample of English-speaking European American (n = 273) and ethnic minority American (n = 194), and Spanish-speaking Latina (n = 199) cervical cancer survivors in the U. S. Results Reliability coefficients (Cronbach's alpha) were 0.76 or higher across ethnic/linguistic groups except for the emotional wellbeing subscale among Spanish-speaking Latinas (alpha = 0.64). Factor analyses demonstrated overall measurement equivalence across groups with some ethnic/linguistic variations: there were greater differences between linguistic groups than between ethnic groups. Additionally, the scale's factor structure was less satisfactory for Spanish-speaking Latinas. The subscales had good concurrent validity with appropriate subscales of the Short Form (SF)-12 and Rand/SF-36 General Health subscale (Pearson's r 0.53-0.66), suggesting each subscale was assessing its intended construct. Conclusion The overall psychometric properties of the FACT-G were cross-culturally equivalent. However, more validation studies are needed for non-English speaking populations particularly with emotional wellbeing. In addition, disaggregated analyses on linguistic groups are recommended unless cross-cultural equivalence is established.