Translation and preliminary validation of the English version of the DUX questionnaire for lower extremity bone tumor patients (Bt-DUX): a disease-specific measure for quality of life.

PURPOSE: To translate the Dutch DUX questionnaire for lower extremity bone tumor patients (Bt-DUX), a disease-specific quality of life (QoL) instrument, into the English (UK) language and preliminary validate the English version in patients who were treated for lower-extremity bone tumors. METHODS: Adaptation and translation process included forward translation, back-translation, and a review of the back-translation by an expert committee. Internal consistency and validity of the translated questionnaire were examined in a sample of adolescents treated for lower extremity osteosarcoma in the United Kingdom. Assessments included the Bt-DUX, the Toronto Extremity Salvage Score (TESS), the Short Form (SF)-36, and the TNO-AZL Questionnaire for Adult's Quality of Life (TAAQOL). RESULTS: Seventeen patients (7 ♂ and 10 ♀), median age 19.9 (range: 16-25) years completed the questionnaires. Mean Bt-DUX score was 38.8 (range: 23-78), with Cronbach's α being 0.95 domain-total correlations ranged between 0.84 and 0.93 (P < 0.01). Spearman's correlation coefficients between the Bt-DUX total and domain scores and corresponding TAAQOL and SF-36 scores were overall moderate to good and reaching statistical significance in a most cases. CONCLUSION: Preliminary evidence suggests that the English Bt-DUX translation is a valid disease-specific instrument for evaluating QoL of adolescents with lower extremity bone cancer.