Cross-cultural validation of the UCLA prostate cancer index.

OBJECTIVES: To explore the impact of cross-cultural differences on University of California, Los Angeles, Prostate Cancer Index (PCI) reliability and validity, which is unknown. The PCI represents the most widely used prostate cancer-specific health-related quality-of-life assessment tool.
METHODS: The PCI sexual and urinary scales, the RAND SF-36 survey, and the Prostate Outcomes Research Team (PORT) prostate cancer treatment complication profile were self-administered. The principal sample consisted of 2415 men (anglophone 256, francophone 2159) treated with radical prostatectomy in Quebec between 1988 and 1996. An additional 35 men (anglophone 17, francophone 18) formed the retest sample.
RESULTS: The PCI demonstrated excellent internal consistency and test-retest reliability in tests based on the entire cohort and in tests addressing the two linguistically different groups. The instrument showed a lack of convergence with the SF-36 scales, confirming the distinctness of the generic and prostate cancer-specific constructs. The PCI sexual scales converged with the aggregate PORT sexual items (r = 0.8), and the PCI urinary scales were strongly related to the aggregate PORT urinary items (r = 0.7). Convergence between PCI urinary bother and function was strong (r = 0.8), but only moderate convergence was noted between PCI sexual bother and function (r = 0.4). The relation between bother and function in both urinary and sexual domains was weaker in anglophone participants relative to their francophone counterparts.
CONCLUSIONS: The PCI is reliable and, at best, only modestly affected by cultural differences when administered to culturally distinct English-speaking men or when translated into French.