Psychological distress in prostate cancer: Validation of the K10 scale using a crossover randomized clinical trial.

Introduction: Men diagnosed with prostate cancer (PCa) experience substantial psychological distress. Despite this, the use of screening tools in this population is limited and understudied. This study evaluates the validity of the Kessler Psychological Distress Scale (K10) as a psychological distress screening tool in men undergoing curative PCa treatment.

Methods: Participants in a PCa psychological distress prevention program (n=128) were assessed at baseline, six months, and 12 months using the K10. Exploratory (EFA) and confirmatory factor analysis (CFA) examined the scale's factor structure. Receiver operating characteristic (ROC) analyses evaluated sensitivity, specificity, and predictive values for depression and anxiety. Logistic regression assessed the impact of cutoffs on clinical psychological distress.

Results: EFA identified a single-factor structure (factor loadings: 0.59-0.96, variance explained: 76%). CFA confirmed model-fit (CFI=0.905; SRMR=0.042). ROC analysis demonstrated excellent predictive ability (area under the curve [AUC] 0.98, 95% confidence interval [CI] 0.95-1.0 for depression; 0.92, 95% CI 0.86-0.98 for anxiety). Youden's index suggested K10 thresholds of ≥17.5 (depression) and ≥16.5 (anxiety), although these cutoffs lacked sensitivity. With standard K10≥20 cutoffs, significant differences were observed between intervention and control groups at six months (adjusted odds ratio [aOR] 3.59, 95% CI 1.12-11.51, p=0.031) and 12 months (aOR 4.41, 95% CI 1.35-4.41, p=0.014), consistent with prior findings.

Conclusions: The K10 is valid and reliable for this population, demonstrating excellent internal consistency; however, lower cutoffs (K10≥16.5, K10≥17.5) may reduce sensitivity. The standard K10≥20 threshold remains preferable for detecting distress and evaluating intervention effects in men with PCa.