title: Individualized early death and long-term survival prediction after stereotactic radiosurgery for brain metastases of non-small cell lung cancer: Two externally validated nomograms.
abstract: Commonly used clinical models for survival prediction after stereotactic radiosurgery (SRS) for brain metastases (BMs) are limited by the lack of individual risk scores and disproportionate prognostic groups. In this study, two nomograms were developed to overcome these limitations.
  
  
  
  495 patients with BMs of NSCLC treated with SRS for a limited number of BMs in four Dutch radiation oncology centers were identified and divided in a training cohort (n=214, patients treated in one hospital) and an external validation cohort n=281, patients treated in three other hospitals). Using the training cohort, nomograms were developed for prediction of early death (<3months) and long-term survival (>12months) with prognostic factors for survival. Accuracy of prediction was defined as the area under the curve (AUC) by receiver operating characteristics analysis for prediction of early death and long term survival. The accuracy of the nomograms was also tested in the external validation cohort.
  
  
  
  Prognostic factors for survival were: WHO performance status, presence of extracranial metastases, age, GTV largest BM, and gender. Number of brain metastases and primary tumor control were not prognostic factors for survival. In the external validation cohort, the nomogram predicted early death statistically significantly better (p<0.05) than the unfavorable groups of the RPA, DS-GPA, GGS, SIR, and Rades 2015 (AUC=0.70 versus range AUCs=0.51-0.60 respectively). With an AUC of 0.67, the other nomogram predicted 1year survival statistically significantly better (p<0.05) than the favorable groups of four models (range AUCs=0.57-0.61), except for the SIR (AUC=0.64, p=0.34). The models are available on www.predictcancer.org.
  
  
  
  The nomograms predicted early death and long-term survival more accurately than commonly used prognostic scores after SRS for a limited number of BMs of NSCLC. Moreover these nomograms enable individualized probability assessment and are easy into use in routine clinical practice.
authors.affiliation: Department of Radiation Oncology (MAASTRO Clinic), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands. Electronic address: jaap.zindler@maastro.nl.
authors.forename: Jaap D
authors.initials: JD
authors.lastname: Zindler
authors.affiliation: Department of Radiation Oncology (MAASTRO Clinic), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands.
authors.forename: Arthur
authors.initials: A
authors.lastname: Jochems
authors.affiliation: Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Lagerwaard
authors.affiliation: Department of Radiation Oncology (MAASTRO Clinic), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands.
authors.forename: Rosemarijne
authors.initials: R
authors.lastname: Beumer
authors.affiliation: Department of Radiation Oncology (MAASTRO Clinic), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands; Institute of Radiooncology, Helmholtz-Zentrum Dresden-Rossendorf, Germany.
authors.forename: Esther G C
authors.initials: EGC
authors.lastname: Troost
authors.affiliation: Department of Radiation Oncology (MAASTRO Clinic), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands.
authors.forename: Daniëlle B P
authors.initials: DBP
authors.lastname: Eekers
authors.affiliation: Department of Radiation Oncology (MAASTRO Clinic), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands.
authors.forename: Inge
authors.initials: I
authors.lastname: Compter
authors.affiliation: Department of Radiation Oncology, Catharina Hospital Eindhoven, The Netherlands.
authors.forename: Peter-Paul
authors.initials: PP
authors.lastname: van der Toorn
authors.affiliation: Department of Radiation Oncology, Verbeeten Institute, Tilburg, The Netherlands.
authors.forename: Marion
authors.initials: M
authors.lastname: Essers
authors.affiliation: Department of Radiation Oncology, Verbeeten Institute, Tilburg, The Netherlands.
authors.forename: Bing
authors.initials: B
authors.lastname: Oei
authors.affiliation: Department of Radiation Oncology, Catharina Hospital Eindhoven, The Netherlands.
authors.forename: Coen W
authors.initials: CW
authors.lastname: Hurkmans
authors.affiliation: Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Anna M E
authors.initials: AME
authors.lastname: Bruynzeel
authors.affiliation: Department of Radiation Oncology (MAASTRO Clinic), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands.
authors.forename: Geert
authors.initials: G
authors.lastname: Bosmans
authors.affiliation: Department of Radiation Oncology (MAASTRO Clinic), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands.
authors.forename: Ans
authors.initials: A
authors.lastname: Swinnen
authors.affiliation: Department of Radiation Oncology (MAASTRO Clinic), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands.
authors.forename: Ralph T H
authors.initials: RTH
authors.lastname: Leijenaar
authors.affiliation: Department of Radiation Oncology (MAASTRO Clinic), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands.
authors.forename: Philippe
authors.initials: P
authors.lastname: Lambin
mesh_terms: D000368:Aged; D019540:Area Under Curve; D001932:Brain Neoplasms / Q000532:radiotherapy / Q000556:secondary*; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D049451:Nomograms; D011379:Prognosis; D016634:Radiosurgery / Q000009:adverse effects
keywords: Individualized brain metastases; Prognostic models; Stereotactic radiosurgery