Developing a nomogram for predicting intravesical recurrence after radical nephroureterectomy: a retrospective cohort study of mainland Chinese patients

Objective: To evaluate the role of Ki-67 in predicting subsequent intravesical recurrence following radical nephroureterectomy and to develop a predictive nomogram for upper tract urothelial carcinoma patients.

Methods: This retrospective analysis involved 489 upper tract urothelial carcinoma patients who underwent radical nephroureterectomy with bladder cuff excision. The data set was randomly split into a training cohort of 293 patients and a validation cohort of 196 patients. Immunohistochemical analysis was used to assess the immunoreactivity of the biomarker Ki-67 in the tumor tissues. A multivariable Cox regression model was utilized to identify independent intravesical recurrence predictors after radical nephroureterectomy before constructing a nomographic model. Predictive accuracy was quantified using time-dependent receiver operating characteristic curve. Decision curve analysis was performed to evaluate the clinical benefit of models.

Results: With a median follow-up of 54 months, intravesical recurrence developed in 28.2% of this sample (n = 137). Tumor location, multifocality, pathological T stage, surgical approach, bladder cancer history and Ki-67 expression levels were independently associated with intravesical recurrence (all P < 0.05). The full model, which intercalated Ki-67 with traditional clinicopathological parameters, outperformed both the basic model and Xylinas' model in terms of discriminative capacity (all P < 0.05). Decision-making analysis suggests that the more comprehensive model can also improve patients' net benefit.

Conclusions: This new model, which intercalates the Ki-67 biomarker with traditional clinicopathological factors, appears to be more sensitive than nomograms previously tested across mainland Chinese populations. The findings suggest that Ki-67 could be useful for determining risk-stratified surveillance protocols following radical nephroureterectomy and in generating an individualized strategy based around intravesical recurrence predictions.