Abstract
BackgroundIn this study, we aimed to propose a validated prediction model for disease‐free survival (DFS) after radical nephroureterectomy (RNU) in a Korean population with upper urinary tract urothelial carcinoma (UTUC).MethodsWe performed a retrospective review of 1561 cases of UTUC who underwent either open RNU (ONU, n = 906) or laparoscopic RNU (LNU, n = 615) from five tertiary Korean institutions between January 2000 and December 2012. Data were used to develop a prediction model using the Cox proportional hazards model. Prognostic factors were selected using the backward variable selection method. The prediction model performance was investigated using Harrell's concordance index (C‐index) and Hosmer‐Lemeshow type 2 statistics. Internal validation was performed using a bootstrap approach, and the National Cancer Center data set (n = 128) was used for external validation.ResultsA best‐fitting prediction model with seven significant factors was developed. The C‐index and two Hosmer‐Lemeshow type statistics of the prediction model were 0.785 (95% CI, 0.755‐0.815), 4.810 (P = 0.8506), and 5.285 (P = 0.8088). The optimism‐corrected estimate through the internal validation was 0.774 (95% CI, 0.744‐0.804) and the optimism‐corrected calibration curve was close to the ideal line with mean absolute error = 0.012. In external validation, the discrimination was 0.657 (95% CI, 0.560‐0.755) and the two calibration statistics were 0.790 (P = 0.9397) and 3.103 (P = 0.5408), respectively.ConclusionA validated prediction model based on a large Korean RNU cohort was developed with acceptable performance to estimate DFS in patients with UTUC.
Highlights
In this study, we aimed to propose a validated prediction model for disease‐free survival (DFS) after radical nephroureterectomy (RNU) in a Korean population with upper urinary tract urothelial carcinoma (UTUC)
The results showed similar predicted and observed values in the development set, but the results were meaningless in the external validation set
A population‐based US study found that African‐American patients with UTUC had a shorter survival than other ethnic groups,[1] and Chinese people had a higher incidence of UTUC due to their lifetime intake of herbal tea.[20]
Summary
Upper urinary tract urothelial carcinomas (UTUC) are relatively rare, accounting for 5%‐10% of urothelial tumors, and their incidence has slowly increased over the past 30 years.[1]. Studies on UTUC are lacking, especially concerning prognosis in Korea. Predicting disease‐free survival (DFS) may optimize follow‐ up and improve post‐RNU management, such as adjuvant chemotherapy, which has been suggested without available level 1 evidence.[4]. 3‐5‐year relative survival statistics are often used to measure cancer control and assess international comparisons.[2,3,5]. Nomograms have been built to integrate independent prognostic variables to better individualize and predict patient prognosis.[2,6]. Initial cancer prognosis assessment at surgery helps to select post‐RNU therapy and follow‐up. Large‐scale studies are necessary to increase a nomogram's accuracy and validate it with an additional patient cohort. The aim of the current study was to determine a prediction model of DFS and OS of UTUC after RNU using a large, multicenter, Korean cohort, and to validate the nomogram model A nomogram was developed from Western UTUC cohorts,[2,7-10] and the few Asian patient‐based nomograms have incorporated small cohorts of patients.[6,8,11] the aim of the current study was to determine a prediction model of DFS and OS of UTUC after RNU using a large, multicenter, Korean cohort, and to validate the nomogram model
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