BACKGROUND: In an exploratory subanalysis of the European Organisation for Research and Treatment of Cancer and National Cancer Institute of Canada (EORTC/NCIC) trial data, Gorlia et al. identified a variety of factors that were predictive of overall survival, including therapy administered, age, extent of surgery, mini-mental score, administration of corticosteroids, World Health Organization (WHO) performance status, and O-methylguanine-DNA methyltransferase (MGMT) promoter methylation status. Gorlia et al. developed 3 nomograms, each intended to predict the survival times of patients with newly diagnosed glioblastoma on the basis of individual-specific combinations of prognostic factors. These are available online as a "GBM Calculator" and are intended for use in patient counseling. This study is an external validation of this calculator. METHOD: One hundred eighty-seven patients from 2 UK neurosurgical units who had histologically confirmed glioblastoma (WHO grade IV) had their information at diagnosis entered into the GBM calculator. A record was made of the actual and predicted median survival time for each patient. Statistical analysis was performed to assess the accuracy, precision, correlation, and discrimination of the calculator. RESULTS: The calculator gives both inaccurate and imprecise predictions. Only 23% of predictions were within 25% of the actual survival, and the percentage bias is 140% in our series. The coefficient of variance is 76%, where a smaller percentage would indicate greater precision. There is only a weak positive correlation between the predicted and actual survival among patients (R(2) of 0.07). Discrimination is inadequate as measured by a C-index of 0.62. CONCLUSIONS: The authors would not recommend the use of this tool in patient counseling. If departments were considering its use, we would advise that a similar validating exercise be undertaken.
BACKGROUND: In an exploratory subanalysis of the European Organisation for Research and Treatment of Cancer and National Cancer Institute of Canada (EORTC/NCIC) trial data, Gorlia et al. identified a variety of factors that were predictive of overall survival, including therapy administered, age, extent of surgery, mini-mental score, administration of corticosteroids, World Health Organization (WHO) performance status, and O-methylguanine-DNA methyltransferase (MGMT) promoter methylation status. Gorlia et al. developed 3 nomograms, each intended to predict the survival times of patients with newly diagnosed glioblastoma on the basis of individual-specific combinations of prognostic factors. These are available online as a "GBM Calculator" and are intended for use in patient counseling. This study is an external validation of this calculator. METHOD: One hundred eighty-seven patients from 2 UK neurosurgical units who had histologically confirmed glioblastoma (WHO grade IV) had their information at diagnosis entered into the GBM calculator. A record was made of the actual and predicted median survival time for each patient. Statistical analysis was performed to assess the accuracy, precision, correlation, and discrimination of the calculator. RESULTS: The calculator gives both inaccurate and imprecise predictions. Only 23% of predictions were within 25% of the actual survival, and the percentage bias is 140% in our series. The coefficient of variance is 76%, where a smaller percentage would indicate greater precision. There is only a weak positive correlation between the predicted and actual survival among patients (R(2) of 0.07). Discrimination is inadequate as measured by a C-index of 0.62. CONCLUSIONS: The authors would not recommend the use of this tool in patient counseling. If departments were considering its use, we would advise that a similar validating exercise be undertaken.
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Authors: Connor W Hoban; Lauren J Beesley; Emily L Bellile; Yilun Sun; Matthew E Spector; Gregory T Wolf; Jeremy M G Taylor; Andrew G Shuman Journal: Cancer Date: 2017-11-07 Impact factor: 6.860
Authors: Amandine Etcheverry; Marc Aubry; Ahmed Idbaih; Elodie Vauleon; Yannick Marie; Philippe Menei; Rachel Boniface; Dominique Figarella-Branger; Lucie Karayan-Tapon; Veronique Quillien; Marc Sanson; Marie de Tayrac; Jean-Yves Delattre; Jean Mosser Journal: PLoS One Date: 2014-09-18 Impact factor: 3.240
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