Patient-reported outcome after radical cystectomy: translation and psychometric validation of the Swedish version of the Functional Assessment of Cancer Therapy Scale Vanderbilt Cystectomy Index

Abstract

Objective: The aim of this study was to translate and validate the Swedish version of the Functional Assessment of Cancer Therapy Scale – Vanderbilt Cystectomy Index (FACT-VCI).Materials and methods: For adaptation into Swedish, a multiprofessional team was used for translation including cultural adjustment, followed by back-translation. Test and retest in 10 individuals was followed by assessing metric properties in 75 consecutive patients with bladder cancer treated with radical cystectomy. Reliability and internal consistency were measured by Cronbach’s alpha. Face validity was tested with two laypersons and construct validity was tested by correlation to the dimensions in the Functional Assessment of Cancer Therapy Scale – General (FACT-G).Results: The translated Swedish instrument showed validity and reliability similar to the original, and the results were comparable to published studies using FACT-VCI. The correlation between the VCI sum score and FACT-G dimensions was significant in all dimensions and the item-total correlation was over 0.3; therefore, the construct validity was acceptable. In addition, it was possible to detect differences in separate items in the translated version of FACT-VCI between age groups, type of diversion and those treated with chemotherapy, even though the samples were small.Conclusions: The Swedish version of FACT-VCI is a valid and reliable instrument for use in the follow-up of patients with bladder cancer treated with urinary diversion. To measure changes after surgery, preoperative assessment with the related FACT-G instrument is advisable.