Health-related quality of life in Japanese patients with bladder cancer measured by a newly developed Japanese version of the Bladder Cancer Index

INTRODUCTION: We validated a Japanese version of the Bladder Cancer Index (BCI) as a tool for measuring health-related quality of life (HRQOL) in bladder cancer patients treated with various surgical procedures. METHODS: The reliability and validity of the Japanese BCI were examined in 397 Japanese patients with bladder cancer via cross-sectional analysis. The patients simultaneously completed the Short Form (SF)-12, EQ-5D, and the Functional Assessment of Cancer Therapy-General and Bladder (FACT-G and FACT-BL). The differences in BCI subscales among various treatment groups were analyzed. RESULTS: This study involved 397 patients (301 males and 96 females), with a mean age of 70 years and a median disease duration of 29 months (IQR: 12–66 months). Of these patients, 221 underwent transurethral resection of a bladder tumor, and 176 patients underwent radical cystectomy (ileal conduit: 101 patients, ileal neobladder: 49, and ureterostomy: 26). Cronbach’s alpha coefficient was ≥ 0.78 for all subscales, except the bowel bother subscale. Despite moderate correlations being detected between the function and bother score in urinary and bowel domains, the sexual function score was inversely correlated with the sexual bother score (r = − 0.19). A missing value percentage of > 15% was associated with old age (p < 0.05). The mean domain scores differed significantly among distinct clinically relevant treatment groups. CONCLUSIONS: Although revisions are needed to make it easier for elderly patients to comprehend, we confirmed the reliability and validity of the Japanese BCI. The Japanese BCI could be used for cross-cultural assessments of HRQOL in bladder cancer patients. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10147-020-01770-2) contains supplementary material, which is available to authorized users.