Klaus Müller1, Guido Henke2, Inge Compter3, André O von Bueren4, Carsten Friedrich5, Geert Janssens6, Christof M Kramm4, Thomas Hundsberger7, Frank Paulsen8, Rolf-Dieter Kortmann9, Isabella Zwiener10, Brigitta G Baumert11. 1. Department of Radiation Oncology, University of Leipzig Medical Center, Leipzig, Germany. Electronic address: Klaus.Mueller@medizin.uni-leipzig.de. 2. Department of Radiation Oncology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland; Department of Radiooncology, University Hospital Tübingen, Tübingen, Germany. 3. Department of Radiation Oncology (MAASTRO), GROW (School for Oncology & Developmental Biology), Maastricht University Medical Centre, Maastricht, The Netherlands. 4. Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, University Medical Center Goettingen, Goettingen, Germany. 5. Division of Pediatric Oncology, Hematology and Hemostaseology, Department of Woman's and Children's Health, University Hospital Leipzig, Leipzig, Germany. 6. Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. 7. Departments of Neurology and Haematology/Oncology, Cantonal Hospital St. Gallen, St. Gallen, Switzerland. 8. Department of Radiooncology, University Hospital Tübingen, Tübingen, Germany. 9. Department of Radiation Oncology, University of Leipzig Medical Center, Leipzig, Germany. 10. Institute for Medical Biostatistics, Epidemiology and Informatics, University Medical Center Mainz, Mainz, Germany. 11. Department of Radiation Oncology (MAASTRO), GROW (School for Oncology & Developmental Biology), Maastricht University Medical Centre, Maastricht, The Netherlands; Department of Radiation Oncology, MediClin Robert Janker Clinic & University of Bonn Med Centre, Clinical Cooperation Unit Neurooncology, Bonn, Germany.
Abstract
PURPOSE: We aimed to validate a controversial prognostic model for the survival of relapsed malignant glioma patients after reirradiation with an independent, multicentric patient cohort. METHODS AND MATERIALS: A total of 165 malignant glioma patients underwent reirradiation at 4 different institutions between 1994 and 2012. Twenty-two patients had a good (score 1), 44 had a moderate (score 2), and 99 had a poor prognosis (score 3 or 4). Four statistical methods were used to validate the prognostic model: First, we compared survival according to prognostic group in the construction and the validation cohort by visual comparison of the respective Kaplan-Meier plots. Second, discrimination was quantified by calculating hazard ratios for death for each prognostic group, with the worst prognostic group serving as the reference. Calibration was assessed by a calibration plot for the time point 12 months after reirradiation. Finally, we compared the predictive performance of the score and a hypothetical prognostic model ignoring all predictor variables over time by means of a prediction error curve. RESULTS: On visual validation, the survival curves of the 3 patient groups with good, moderate, and poor prognoses nicely separated from each other. Median survival rates after reirradiation were 17.9, 9.0, and 7.7 months in the patient groups with good, moderate, and poor prognosis, respectively. Hazard ratios confirmed satisfactory discrimination. Calibration was satisfactory for all and most accurate for the worst prognostic group. The score improved the prognostic performance in comparison to the "zero-model." CONCLUSIONS: We successfully validated a prognostic model for the survival of malignant glioma patients after reirradiation with a multicentric, independent dataset. Being reliable and easy to handle, the model can be useful in personalized patient counseling and clinical decision-making.
PURPOSE: We aimed to validate a controversial prognostic model for the survival of relapsed malignant gliomapatients after reirradiation with an independent, multicentric patient cohort. METHODS AND MATERIALS: A total of 165 malignant gliomapatients underwent reirradiation at 4 different institutions between 1994 and 2012. Twenty-two patients had a good (score 1), 44 had a moderate (score 2), and 99 had a poor prognosis (score 3 or 4). Four statistical methods were used to validate the prognostic model: First, we compared survival according to prognostic group in the construction and the validation cohort by visual comparison of the respective Kaplan-Meier plots. Second, discrimination was quantified by calculating hazard ratios for death for each prognostic group, with the worst prognostic group serving as the reference. Calibration was assessed by a calibration plot for the time point 12 months after reirradiation. Finally, we compared the predictive performance of the score and a hypothetical prognostic model ignoring all predictor variables over time by means of a prediction error curve. RESULTS: On visual validation, the survival curves of the 3 patient groups with good, moderate, and poor prognoses nicely separated from each other. Median survival rates after reirradiation were 17.9, 9.0, and 7.7 months in the patient groups with good, moderate, and poor prognosis, respectively. Hazard ratios confirmed satisfactory discrimination. Calibration was satisfactory for all and most accurate for the worst prognostic group. The score improved the prognostic performance in comparison to the "zero-model." CONCLUSIONS: We successfully validated a prognostic model for the survival of malignant gliomapatients after reirradiation with a multicentric, independent dataset. Being reliable and easy to handle, the model can be useful in personalized patient counseling and clinical decision-making.
Authors: Andra V Krauze; Albert Attia; Steve Braunstein; Michael Chan; Stephanie E Combs; Rainer Fietkau; John Fiveash; John Flickinger; Anca Grosu; Steven Howard; Carsten Nieder; Maximilian Niyazi; Lindsay Rowe; Dee Dee Smart; Christina Tsien; Kevin Camphausen Journal: Radiat Oncol Date: 2017-12-01 Impact factor: 3.481