This study will evaluate the cross-cultural adaptation, validity, and reliability of the Turkish version of the UCLA Prostate Cancer Index in men diagnosed with prostate cancer. The original instrument will be translated and culturally adapted following standardized procedures. The psychometric properties of the Turkish version will be examined in patients attending routine follow-up visits at a urology clinic.

Internal consistency will be assessed using Cronbach's alpha coefficients, and test-retest reliability will be evaluated using intraclass correlation coefficients (ICC) in a subset of participants. Measurement error will be determined by calculating the standard error of measurement (SEM) and the smallest real difference at the 95% confidence level (SRD95). Construct validity will be examined through exploratory factor analysis, and convergent validity will be assessed by testing predefined hypotheses regarding correlations between the UCLA Prostate Cancer Index and established quality-of-life instruments (SF-36 and EORTC QLQ-PR25).

The findings are expected to provide a reliable and valid prostate cancer-specific quality-of-life assessment tool for use in Turkish-speaking populations.

Inclusion Criteria:

• Male patients
• Diagnosis of prostate cancer

Exclusion Criteria:

• Severe psychiatric or mental disorders that may impair the ability to complete the questionnaires properly
• Presence of congenital deformities

This study includes participants who self-identify as male, as prostate cancer is a disease affecting individuals with male reproductive anatomy.

The study population consists of men aged 45 years and older who have been diagnosed with prostate cancer and are attending routine follow-up visits at a urology outpatient clinic in Türkiye.