The Cancer of the Bladder Risk Assessment (COBRA) score for predicting cancer-specific survival after radical cystectomy for urothelial carcinoma of the bladder

External validation in a cohort of Korean patients

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Objectives: To validate the Cancer of the Bladder Risk Assessment (COBRA) score for predicting cancer-specific survival (CSS) in comparison with the American Joint Committee on Cancer (AJCC) staging system using an external cohort of urothelial carcinoma of the bladder (UCB) from South Korea. Materials and Methods: The final validation cohort consisted of 855 patients who underwent radical cystectomy (RC) for UCB in a single institution. The impact of the COBRA score on CSS was estimated using Cox proportional hazard models. Discrimination accuracy was quantified with concordance index. Calibration plots were used to determine the relationship between model-predicted CSS and actual CSS at 2 years and 5 years after RC. Clinical usefulness of the COBRA score was assessed using decision curve analyses. Results: One-point increase in the COBRA score (range, 0–6) was closely related to a 1.50-fold increase (95% confidence interval [CI]: 1.39–1.62) in the risk of death from UCB. Discrimination accuracies of the COBRA score and AJCC staging system for CSS at 5 years were 70.6% (95% CI: 67.2–74.0) and 68.3% (95% CI: 65.0–71.6), respectively. Compared to the AJCC staging system, the COBRA score was generally well-calibrated for predicting CSS at 2 and 5 years after RC. On decision curve analyses, the use of the COBRA score showed more clinical net benefits across a wide range of threshold probabilities than the AJCC staging system. Conclusions: Our external validation results suggest that although the COBRA score is not perfectly accurate, it shows a reasonable level of discriminative ability, adequate calibration, and meaningful net benefit gain for predicting CSS after RC in a Korean UCB cohort.

Original languageEnglish
Pages (from-to)470-477
Number of pages8
JournalUrologic Oncology: Seminars and Original Investigations
Volume37
Issue number7
DOIs
StatePublished - 1 Jul 2019

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Cystectomy
Urinary Bladder Neoplasms
Urinary Bladder
Carcinoma
Survival
Neoplasm Staging
Neoplasms
Decision Support Techniques
Confidence Intervals
Calibration
Republic of Korea
Proportional Hazards Models

Keywords

  • Carcinoma
  • Cystectomy
  • Prognosis
  • Transitional cell
  • Urinary bladder neoplasms

Cite this

@article{b88862df08514fcdb1d7236efbe61251,
title = "The Cancer of the Bladder Risk Assessment (COBRA) score for predicting cancer-specific survival after radical cystectomy for urothelial carcinoma of the bladder: External validation in a cohort of Korean patients",
abstract = "Objectives: To validate the Cancer of the Bladder Risk Assessment (COBRA) score for predicting cancer-specific survival (CSS) in comparison with the American Joint Committee on Cancer (AJCC) staging system using an external cohort of urothelial carcinoma of the bladder (UCB) from South Korea. Materials and Methods: The final validation cohort consisted of 855 patients who underwent radical cystectomy (RC) for UCB in a single institution. The impact of the COBRA score on CSS was estimated using Cox proportional hazard models. Discrimination accuracy was quantified with concordance index. Calibration plots were used to determine the relationship between model-predicted CSS and actual CSS at 2 years and 5 years after RC. Clinical usefulness of the COBRA score was assessed using decision curve analyses. Results: One-point increase in the COBRA score (range, 0–6) was closely related to a 1.50-fold increase (95{\%} confidence interval [CI]: 1.39–1.62) in the risk of death from UCB. Discrimination accuracies of the COBRA score and AJCC staging system for CSS at 5 years were 70.6{\%} (95{\%} CI: 67.2–74.0) and 68.3{\%} (95{\%} CI: 65.0–71.6), respectively. Compared to the AJCC staging system, the COBRA score was generally well-calibrated for predicting CSS at 2 and 5 years after RC. On decision curve analyses, the use of the COBRA score showed more clinical net benefits across a wide range of threshold probabilities than the AJCC staging system. Conclusions: Our external validation results suggest that although the COBRA score is not perfectly accurate, it shows a reasonable level of discriminative ability, adequate calibration, and meaningful net benefit gain for predicting CSS after RC in a Korean UCB cohort.",
keywords = "Carcinoma, Cystectomy, Prognosis, Transitional cell, Urinary bladder neoplasms",
author = "Kim, {Hyung Suk} and Cheol Kwak and Kim, {Hyeon Hoe} and Ku, {Ja Hyeon}",
year = "2019",
month = "7",
day = "1",
doi = "10.1016/j.urolonc.2019.03.006",
language = "English",
volume = "37",
pages = "470--477",
journal = "Urologic Oncology: Seminars and Original Investigations",
issn = "1078-1439",
publisher = "Elsevier Inc.",
number = "7",

}

TY - JOUR

T1 - The Cancer of the Bladder Risk Assessment (COBRA) score for predicting cancer-specific survival after radical cystectomy for urothelial carcinoma of the bladder

T2 - External validation in a cohort of Korean patients

AU - Kim, Hyung Suk

AU - Kwak, Cheol

AU - Kim, Hyeon Hoe

AU - Ku, Ja Hyeon

PY - 2019/7/1

Y1 - 2019/7/1

N2 - Objectives: To validate the Cancer of the Bladder Risk Assessment (COBRA) score for predicting cancer-specific survival (CSS) in comparison with the American Joint Committee on Cancer (AJCC) staging system using an external cohort of urothelial carcinoma of the bladder (UCB) from South Korea. Materials and Methods: The final validation cohort consisted of 855 patients who underwent radical cystectomy (RC) for UCB in a single institution. The impact of the COBRA score on CSS was estimated using Cox proportional hazard models. Discrimination accuracy was quantified with concordance index. Calibration plots were used to determine the relationship between model-predicted CSS and actual CSS at 2 years and 5 years after RC. Clinical usefulness of the COBRA score was assessed using decision curve analyses. Results: One-point increase in the COBRA score (range, 0–6) was closely related to a 1.50-fold increase (95% confidence interval [CI]: 1.39–1.62) in the risk of death from UCB. Discrimination accuracies of the COBRA score and AJCC staging system for CSS at 5 years were 70.6% (95% CI: 67.2–74.0) and 68.3% (95% CI: 65.0–71.6), respectively. Compared to the AJCC staging system, the COBRA score was generally well-calibrated for predicting CSS at 2 and 5 years after RC. On decision curve analyses, the use of the COBRA score showed more clinical net benefits across a wide range of threshold probabilities than the AJCC staging system. Conclusions: Our external validation results suggest that although the COBRA score is not perfectly accurate, it shows a reasonable level of discriminative ability, adequate calibration, and meaningful net benefit gain for predicting CSS after RC in a Korean UCB cohort.

AB - Objectives: To validate the Cancer of the Bladder Risk Assessment (COBRA) score for predicting cancer-specific survival (CSS) in comparison with the American Joint Committee on Cancer (AJCC) staging system using an external cohort of urothelial carcinoma of the bladder (UCB) from South Korea. Materials and Methods: The final validation cohort consisted of 855 patients who underwent radical cystectomy (RC) for UCB in a single institution. The impact of the COBRA score on CSS was estimated using Cox proportional hazard models. Discrimination accuracy was quantified with concordance index. Calibration plots were used to determine the relationship between model-predicted CSS and actual CSS at 2 years and 5 years after RC. Clinical usefulness of the COBRA score was assessed using decision curve analyses. Results: One-point increase in the COBRA score (range, 0–6) was closely related to a 1.50-fold increase (95% confidence interval [CI]: 1.39–1.62) in the risk of death from UCB. Discrimination accuracies of the COBRA score and AJCC staging system for CSS at 5 years were 70.6% (95% CI: 67.2–74.0) and 68.3% (95% CI: 65.0–71.6), respectively. Compared to the AJCC staging system, the COBRA score was generally well-calibrated for predicting CSS at 2 and 5 years after RC. On decision curve analyses, the use of the COBRA score showed more clinical net benefits across a wide range of threshold probabilities than the AJCC staging system. Conclusions: Our external validation results suggest that although the COBRA score is not perfectly accurate, it shows a reasonable level of discriminative ability, adequate calibration, and meaningful net benefit gain for predicting CSS after RC in a Korean UCB cohort.

KW - Carcinoma

KW - Cystectomy

KW - Prognosis

KW - Transitional cell

KW - Urinary bladder neoplasms

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U2 - 10.1016/j.urolonc.2019.03.006

DO - 10.1016/j.urolonc.2019.03.006

M3 - Article

VL - 37

SP - 470

EP - 477

JO - Urologic Oncology: Seminars and Original Investigations

JF - Urologic Oncology: Seminars and Original Investigations

SN - 1078-1439

IS - 7

ER -