Prognostic value of prostate volume and nomograms for predicting recurrence in patients with non-muscle invasive bladder cancer: a multi-institutional study.

PURPOSE: We conducted an assessment to investigate the impact of prostate volume on the recurrence of patients with non-muscle invasive bladder cancer (NMIBC). Subsequently, we developed and validated nomograms to accurately evaluate recurrence in NMIBC patients. Additionally, we examined the potential improvement in predictive capability achieved by introducing prostate volume as a variable in the model. METHODS: We conducted a retrospective analysis, enrolling 555 eligible patients from seven independent medical institutions across China. We first evaluate recurrence-free survival outcomes in patients with varying prostate volumes. Subsequently, we divided patients into a training cohort and an external validation cohort. Univariate and multivariate Cox regression analyses were conducted within the training cohort. Accordingly, two nomogram models with and without prostate volumes were developed. Their performance was compared by concordance index, calibration curves, receiver operating characteristics curves, and decision curve analysis. Furthermore, a risk classification model utilizing the nomogram incorporating prostate volume was developed. RESULTS: The 3-year recurrence-free survival was markedly lower in patients with large prostate volumes (> 30 ml) compared to those with relatively small prostate volumes (< 30 ml) (p < 0.001). The AUC for the model incorporating prostate volume at 3 years in the training cohort and external validation cohort was 0.828 and 0.811, surpassing the AUC for the model excluding prostate volume at the corresponding intervals, which was 0.796 and 0.778. The 1- and 2-year AUC for the two models also exhibited similar differences. The decision curve analysis results demonstrated the significant superiority of the nomogram incorporating prostate volume over the one without it. CONCLUSION: Our investigation revealed that prostate volume significantly influences recurrence in patients with NMIBC. We successfully developed a more accurate nomogram by introducing prostate volume as a variable and provided new insights to further guide clinical management and individualized treatment of NMIBC patients.