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Title: Validation of the Web-Based IBTR! 2.0 Nomogram to Predict for Ipsilateral Breast Tumor Recurrence After Breast-Conserving Therapy

Abstract

Purpose: To evaluate the IBTR! 2.0 nomogram, which predicts 10-year ipsilateral breast tumor recurrence (IBTR) after breast-conserving therapy with and without radiation therapy for breast cancer, by using a large, external, and independent cancer center database. Methods and Materials: We retrospectively identified 1898 breast cancer cases, treated with breast-conserving therapy and radiation therapy at the University Hospital Leuven from 2000 to 2007, with requisite data for the nomogram variables. Clinicopathologic factors were assessed. Two definitions of IBTR were considered where simultaneous regional or distant recurrence were either censored (conform IBTR! 2.0) or included as event. Validity of the prediction algorithm was tested in terms of discrimination and calibration. Discrimination was assessed by the concordance probability estimate and Harrell's concordance index. The mean predicted and observed 10-year estimates were compared for the entire cohort and for 4 risk groups predefined by nomogram-predicted IBTR risks, and a calibration plot was drawn. Results: Median follow-up was 10.9 years. The 10-year IBTR rates were 1.3% and 2.1%, according to the 2 definitions of IBTR. The validation cohort differed from the development cohort with respect to the administration of hormonal therapy, surgical section margins, lymphovascular invasion, and tumor size. In univariable analysis, younger age (P=.002) and amore » positive nodal status (P=.048) were significantly associated with IBTR, with a trend for the omission of hormonal therapy (P=.061). The concordance probability estimate and concordance index varied between 0.57 and 0.67 for the 2 definitions of IBTR. In all 4 risk groups the model overestimated the IBTR risk. In particular, between the lowest-risk groups a limited differentiation was suggested by the calibration plot. Conclusions: The IBTR! 2.0 predictive model for IBTR in breast cancer patients shows substandard discriminative ability, with an overestimation of the risk in all subgroups.« less

Authors:
 [1];  [2];  [3]; ; ;  [1];  [2];  [1];  [2]; ;  [1];  [2]
  1. Department of Oncology, KU Leuven - University of Leuven, Leuven (Belgium)
  2. (Belgium)
  3. Leuven Biostatistics and Statistical Bioinformatics Center (L-Biostat), KU Leuven - University of Leuven, Leuven (Belgium)
Publication Date:
OSTI Identifier:
22648767
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 95; Journal Issue: 5; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; CALIBRATION; FORECASTING; MAMMARY GLANDS; NEOPLASMS; NOMOGRAMS; RADIATION HAZARDS; RADIOTHERAPY; VALIDATION

Citation Formats

Kindts, Isabelle, E-mail: Isabelle.kindts@uzleuven.be, Department of Radiation Oncology, University Hospitals Leuven, Leuven, Laenen, Annouschka, Peeters, Stephanie, Janssen, Hilde, Depuydt, Tom, Department of Radiation Oncology, University Hospitals Leuven, Leuven, Nevelsteen, Ines, Department of Surgical Oncology, University Hospitals Leuven, Leuven, Van Limbergen, Erik, Weltens, Caroline, and Department of Radiation Oncology, University Hospitals Leuven, Leuven. Validation of the Web-Based IBTR! 2.0 Nomogram to Predict for Ipsilateral Breast Tumor Recurrence After Breast-Conserving Therapy. United States: N. p., 2016. Web. doi:10.1016/J.IJROBP.2016.03.036.
Kindts, Isabelle, E-mail: Isabelle.kindts@uzleuven.be, Department of Radiation Oncology, University Hospitals Leuven, Leuven, Laenen, Annouschka, Peeters, Stephanie, Janssen, Hilde, Depuydt, Tom, Department of Radiation Oncology, University Hospitals Leuven, Leuven, Nevelsteen, Ines, Department of Surgical Oncology, University Hospitals Leuven, Leuven, Van Limbergen, Erik, Weltens, Caroline, & Department of Radiation Oncology, University Hospitals Leuven, Leuven. Validation of the Web-Based IBTR! 2.0 Nomogram to Predict for Ipsilateral Breast Tumor Recurrence After Breast-Conserving Therapy. United States. doi:10.1016/J.IJROBP.2016.03.036.
Kindts, Isabelle, E-mail: Isabelle.kindts@uzleuven.be, Department of Radiation Oncology, University Hospitals Leuven, Leuven, Laenen, Annouschka, Peeters, Stephanie, Janssen, Hilde, Depuydt, Tom, Department of Radiation Oncology, University Hospitals Leuven, Leuven, Nevelsteen, Ines, Department of Surgical Oncology, University Hospitals Leuven, Leuven, Van Limbergen, Erik, Weltens, Caroline, and Department of Radiation Oncology, University Hospitals Leuven, Leuven. Mon . "Validation of the Web-Based IBTR! 2.0 Nomogram to Predict for Ipsilateral Breast Tumor Recurrence After Breast-Conserving Therapy". United States. doi:10.1016/J.IJROBP.2016.03.036.
@article{osti_22648767,
title = {Validation of the Web-Based IBTR! 2.0 Nomogram to Predict for Ipsilateral Breast Tumor Recurrence After Breast-Conserving Therapy},
author = {Kindts, Isabelle, E-mail: Isabelle.kindts@uzleuven.be and Department of Radiation Oncology, University Hospitals Leuven, Leuven and Laenen, Annouschka and Peeters, Stephanie and Janssen, Hilde and Depuydt, Tom and Department of Radiation Oncology, University Hospitals Leuven, Leuven and Nevelsteen, Ines and Department of Surgical Oncology, University Hospitals Leuven, Leuven and Van Limbergen, Erik and Weltens, Caroline and Department of Radiation Oncology, University Hospitals Leuven, Leuven},
abstractNote = {Purpose: To evaluate the IBTR! 2.0 nomogram, which predicts 10-year ipsilateral breast tumor recurrence (IBTR) after breast-conserving therapy with and without radiation therapy for breast cancer, by using a large, external, and independent cancer center database. Methods and Materials: We retrospectively identified 1898 breast cancer cases, treated with breast-conserving therapy and radiation therapy at the University Hospital Leuven from 2000 to 2007, with requisite data for the nomogram variables. Clinicopathologic factors were assessed. Two definitions of IBTR were considered where simultaneous regional or distant recurrence were either censored (conform IBTR! 2.0) or included as event. Validity of the prediction algorithm was tested in terms of discrimination and calibration. Discrimination was assessed by the concordance probability estimate and Harrell's concordance index. The mean predicted and observed 10-year estimates were compared for the entire cohort and for 4 risk groups predefined by nomogram-predicted IBTR risks, and a calibration plot was drawn. Results: Median follow-up was 10.9 years. The 10-year IBTR rates were 1.3% and 2.1%, according to the 2 definitions of IBTR. The validation cohort differed from the development cohort with respect to the administration of hormonal therapy, surgical section margins, lymphovascular invasion, and tumor size. In univariable analysis, younger age (P=.002) and a positive nodal status (P=.048) were significantly associated with IBTR, with a trend for the omission of hormonal therapy (P=.061). The concordance probability estimate and concordance index varied between 0.57 and 0.67 for the 2 definitions of IBTR. In all 4 risk groups the model overestimated the IBTR risk. In particular, between the lowest-risk groups a limited differentiation was suggested by the calibration plot. Conclusions: The IBTR! 2.0 predictive model for IBTR in breast cancer patients shows substandard discriminative ability, with an overestimation of the risk in all subgroups.},
doi = {10.1016/J.IJROBP.2016.03.036},
journal = {International Journal of Radiation Oncology, Biology and Physics},
number = 5,
volume = 95,
place = {United States},
year = {Mon Aug 01 00:00:00 EDT 2016},
month = {Mon Aug 01 00:00:00 EDT 2016}
}