Nomograms for predicting long-term overall survival and disease-specific survival of patients with clear cell renal cell carcinoma

Abstract

Objectives: The aim of this study was to establish comprehensive and practical nomograms, based on significant clinicopathological parameters, for predicting the overall survival (OS) and the disease-specific survival (DSS) of patients with clear cell renal cell carcinoma (ccRCC).

Patients and methods: The data of 35,151 ccRCC patients, diagnosed between 2004 and 2014, were obtained from the database of the Surveillance, Epidemiology, and End Results (SEER) program. The Kaplan-Meier method and Cox proportional hazards regression model were used to evaluate the prognostic effects of multiple clinicopathological variables on survival. Based on Cox models, a nomogram was constructed to predict the probabilities of OS and DSS for an individual patient. The predictive performance of nomograms was evaluated using the concordance index (C-index) and calibration curves.

Results: According to univariate and multivariate analyses, age at diagnosis, sex, race, marital status, surgical approach, tumor node metastasis (TNM) stage, and Fuhrman grade significantly correlated with the survival outcomes. These characteristics were used to establish nomograms. The nomograms showed good accuracy in predicting 3-, 5-, and 10-year OS and DSS, with a C-index of 0.79 (95% CI, 0.79-0.80) for OS and 0.87 (95% CI, 0.86-0.88) for DSS. All calibration curves revealed excellent consistency between predicted and actual survival.

Conclusion: Nomograms were developed to predict death from ccRCC treated with nephrectomy. These new prognostic tools could aid in improving the predictive accuracy of survival outcomes, thus leading to reasonable individualized treatment.

Keywords: clear cell renal cell carcinoma; nomogram; prognosis; survival analysis.

Figure 1

Nomograms for predicting the 3-, 5-, and 10-year OS of ccRCC patients. Note: Instructions for using the nomogram: first, assign the points of each characteristic of the patient by drawing a vertical line from that variable to the points’ scale, then, sum all the points, and draw a vertical line from the total points scale to the 3-, 5-, and 10-year OS to obtain the probability of death. Abbreviations: ccRCC, clear cell renal cell carcinoma; OS, overall survival.

Figure 2

Nomograms for predicting the 3-, 5-, and 10-year DSS of ccRCC patients. Note: Instructions for using the nomogram: first, assign the points of each characteristic of the patient by drawing a vertical line from that variable to the points scale, then, sum all the points, and draw a vertical line from the total points’ scale to the 3-, 5-, and 10-year DSS to obtain the probability of death. Abbreviations: ccRCC, clear cell renal cell carcinoma; DSS, disease-specific survival.

Figure 3

The internal calibration curves for predictions of OS (A) and DSS (B) at 3, 5, and 10 years after operation. Notes: The dashed line represents a perfect match between the nomogram-predicted probability (x-axis) and the actual probability calculated by Kaplan–Meier analysis (y-axis). The cohort was divided into seven equal groups in sample size according to the predicted probability of OS and DSS. Closer distances from the points to the dashed line indicate better agreement between the predicted and actual outcomes. Abbreviations: DSS, disease-specific survival; OS, overall survival.