External validation of an online nomogram in patients undergoing radical nephroureterectomy for upper urinary tract urothelial carcinoma.

BACKGROUND

The objective was to validate an online nomogram developed based on the French collaborative national database on upper urinary tract urothelial carcinoma (UUT-UC) using a different cohort.

METHODS

The study comprised 328 patients with UUT-UC who underwent radical nephroureterectomy. The discrimination of models was quantified using Harrell's concordance index. The relationship between the model-derived and actuarial cancer-specific mortality was graphically explored within calibration plots. Calibration was also assessed using the quartiles of the predicted survival at 3 and 5 years and calculation of the corresponding observed Kaplan-Meier estimates. Clinical net benefit was evaluated constructing decision curve analysis.

RESULTS

The discrimination accuracy of the nomograms at 3 and 5 years was 71.6% and 71.8%, respectively. Although nomograms discriminated well by Kaplan-Meier curves, and log-rank tests were all highly significant, the calibration plots tended to exaggerate the overestimation of mortality between predicted and observed probabilities at 3 and 5 years for survival. When compared with the AJCC/UICC staging system, the nomograms performed well across a wide range of threshold probabilities using decision curve analysis.

CONCLUSION

The online nomogram is a highly accurate prognostic tool for patients with UUT-UC treated with radical nephroureterectomy. The model can provide an accurate estimate of the individual risk of cancer-specific mortality. Further improvement and implementation of novel molecular marker is needed.