External validation of IBTR! 2.0 nomogram for prediction of ipsilateral breast tumor recurrence

Byung Min Lee, Jee Suk Chang, Young Up Cho, Seho Park, Hyung Seok Park, Jee Ye Kim, Joo Hyuk Sohn, Gun Min Kim, Ja Seung Koo, Ki Chang Keum, Chang Ok Suh, Yong Bae Kim

Research output: Contribution to journalArticle

Abstract

Purpose: IBTR! 2.0 nomogram is web-based nomogram that predicts ipsilateral breast tumor recurrence (IBTR). We aimed to validate the IBTR! 2.0 using an external data set. Materials and Methods: The cohort consisted of 2,206 patients, who received breast conserving surgery and radiation therapy from 1992 to 2012 at our institution, where wide surgical excision is been routinely performed. Discrimination and calibration were used for assessing model performance. Patients with predicted 10-year IBTR risk based on an IBTR! 2.0 nomogram score of <3%, 3%–5%, 5%–10%, and >10% were assigned to groups 1, 2, 3, and 4, respectively. We also plotted calibration values to observe the actual IBTR rate against the nomogram-derived 10-year IBTR probabilities. Results: The median follow-up period was 73 months (range, 6 to 277 months). The area under the receiver operating characteristic curve was 0.607, showing poor accordance between the estimated and observed recurrence rate. Calibration plot confirmed that the IBTR! 2.0 nomogram predicted the 10-year IBTR risk higher than the observed IBTR rates in all groups. High discrepancies between nomogram IBTR predictions and observed IBTR rates were observed in overall risk groups. Compared with the original development dataset, our patients had fewer high grade tumors, less margin positivity, and less lymphovascular invasion, and more use of modern systemic therapies. Conclusions: IBTR! 2.0 nomogram seems to have the moderate discriminative ability with a tendency to over-estimating risk rate. Continued efforts are needed to ensure external applicability of published nomograms by validating the program using an external patient population.

Original languageEnglish
Pages (from-to)139-146
Number of pages8
JournalRadiation Oncology Journal
Volume36
Issue number2
DOIs
Publication statusPublished - 2018 Jun

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Nomograms
Breast Neoplasms
Recurrence
Calibration
Segmental Mastectomy
ROC Curve

All Science Journal Classification (ASJC) codes

  • Oncology
  • Radiology Nuclear Medicine and imaging

Cite this

Lee, Byung Min ; Chang, Jee Suk ; Cho, Young Up ; Park, Seho ; Park, Hyung Seok ; Kim, Jee Ye ; Sohn, Joo Hyuk ; Kim, Gun Min ; Koo, Ja Seung ; Keum, Ki Chang ; Suh, Chang Ok ; Kim, Yong Bae. / External validation of IBTR! 2.0 nomogram for prediction of ipsilateral breast tumor recurrence. In: Radiation Oncology Journal. 2018 ; Vol. 36, No. 2. pp. 139-146.
@article{9a9921d19bb0424daa59e66e3532a021,
title = "External validation of IBTR! 2.0 nomogram for prediction of ipsilateral breast tumor recurrence",
abstract = "Purpose: IBTR! 2.0 nomogram is web-based nomogram that predicts ipsilateral breast tumor recurrence (IBTR). We aimed to validate the IBTR! 2.0 using an external data set. Materials and Methods: The cohort consisted of 2,206 patients, who received breast conserving surgery and radiation therapy from 1992 to 2012 at our institution, where wide surgical excision is been routinely performed. Discrimination and calibration were used for assessing model performance. Patients with predicted 10-year IBTR risk based on an IBTR! 2.0 nomogram score of <3{\%}, 3{\%}–5{\%}, 5{\%}–10{\%}, and >10{\%} were assigned to groups 1, 2, 3, and 4, respectively. We also plotted calibration values to observe the actual IBTR rate against the nomogram-derived 10-year IBTR probabilities. Results: The median follow-up period was 73 months (range, 6 to 277 months). The area under the receiver operating characteristic curve was 0.607, showing poor accordance between the estimated and observed recurrence rate. Calibration plot confirmed that the IBTR! 2.0 nomogram predicted the 10-year IBTR risk higher than the observed IBTR rates in all groups. High discrepancies between nomogram IBTR predictions and observed IBTR rates were observed in overall risk groups. Compared with the original development dataset, our patients had fewer high grade tumors, less margin positivity, and less lymphovascular invasion, and more use of modern systemic therapies. Conclusions: IBTR! 2.0 nomogram seems to have the moderate discriminative ability with a tendency to over-estimating risk rate. Continued efforts are needed to ensure external applicability of published nomograms by validating the program using an external patient population.",
author = "Lee, {Byung Min} and Chang, {Jee Suk} and Cho, {Young Up} and Seho Park and Park, {Hyung Seok} and Kim, {Jee Ye} and Sohn, {Joo Hyuk} and Kim, {Gun Min} and Koo, {Ja Seung} and Keum, {Ki Chang} and Suh, {Chang Ok} and Kim, {Yong Bae}",
year = "2018",
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Lee, BM, Chang, JS, Cho, YU, Park, S, Park, HS, Kim, JY, Sohn, JH, Kim, GM, Koo, JS, Keum, KC, Suh, CO & Kim, YB 2018, 'External validation of IBTR! 2.0 nomogram for prediction of ipsilateral breast tumor recurrence', Radiation Oncology Journal, vol. 36, no. 2, pp. 139-146. https://doi.org/10.3857/roj.2018.00059

External validation of IBTR! 2.0 nomogram for prediction of ipsilateral breast tumor recurrence. / Lee, Byung Min; Chang, Jee Suk; Cho, Young Up; Park, Seho; Park, Hyung Seok; Kim, Jee Ye; Sohn, Joo Hyuk; Kim, Gun Min; Koo, Ja Seung; Keum, Ki Chang; Suh, Chang Ok; Kim, Yong Bae.

In: Radiation Oncology Journal, Vol. 36, No. 2, 06.2018, p. 139-146.

Research output: Contribution to journalArticle

TY - JOUR

T1 - External validation of IBTR! 2.0 nomogram for prediction of ipsilateral breast tumor recurrence

AU - Lee, Byung Min

AU - Chang, Jee Suk

AU - Cho, Young Up

AU - Park, Seho

AU - Park, Hyung Seok

AU - Kim, Jee Ye

AU - Sohn, Joo Hyuk

AU - Kim, Gun Min

AU - Koo, Ja Seung

AU - Keum, Ki Chang

AU - Suh, Chang Ok

AU - Kim, Yong Bae

PY - 2018/6

Y1 - 2018/6

N2 - Purpose: IBTR! 2.0 nomogram is web-based nomogram that predicts ipsilateral breast tumor recurrence (IBTR). We aimed to validate the IBTR! 2.0 using an external data set. Materials and Methods: The cohort consisted of 2,206 patients, who received breast conserving surgery and radiation therapy from 1992 to 2012 at our institution, where wide surgical excision is been routinely performed. Discrimination and calibration were used for assessing model performance. Patients with predicted 10-year IBTR risk based on an IBTR! 2.0 nomogram score of <3%, 3%–5%, 5%–10%, and >10% were assigned to groups 1, 2, 3, and 4, respectively. We also plotted calibration values to observe the actual IBTR rate against the nomogram-derived 10-year IBTR probabilities. Results: The median follow-up period was 73 months (range, 6 to 277 months). The area under the receiver operating characteristic curve was 0.607, showing poor accordance between the estimated and observed recurrence rate. Calibration plot confirmed that the IBTR! 2.0 nomogram predicted the 10-year IBTR risk higher than the observed IBTR rates in all groups. High discrepancies between nomogram IBTR predictions and observed IBTR rates were observed in overall risk groups. Compared with the original development dataset, our patients had fewer high grade tumors, less margin positivity, and less lymphovascular invasion, and more use of modern systemic therapies. Conclusions: IBTR! 2.0 nomogram seems to have the moderate discriminative ability with a tendency to over-estimating risk rate. Continued efforts are needed to ensure external applicability of published nomograms by validating the program using an external patient population.

AB - Purpose: IBTR! 2.0 nomogram is web-based nomogram that predicts ipsilateral breast tumor recurrence (IBTR). We aimed to validate the IBTR! 2.0 using an external data set. Materials and Methods: The cohort consisted of 2,206 patients, who received breast conserving surgery and radiation therapy from 1992 to 2012 at our institution, where wide surgical excision is been routinely performed. Discrimination and calibration were used for assessing model performance. Patients with predicted 10-year IBTR risk based on an IBTR! 2.0 nomogram score of <3%, 3%–5%, 5%–10%, and >10% were assigned to groups 1, 2, 3, and 4, respectively. We also plotted calibration values to observe the actual IBTR rate against the nomogram-derived 10-year IBTR probabilities. Results: The median follow-up period was 73 months (range, 6 to 277 months). The area under the receiver operating characteristic curve was 0.607, showing poor accordance between the estimated and observed recurrence rate. Calibration plot confirmed that the IBTR! 2.0 nomogram predicted the 10-year IBTR risk higher than the observed IBTR rates in all groups. High discrepancies between nomogram IBTR predictions and observed IBTR rates were observed in overall risk groups. Compared with the original development dataset, our patients had fewer high grade tumors, less margin positivity, and less lymphovascular invasion, and more use of modern systemic therapies. Conclusions: IBTR! 2.0 nomogram seems to have the moderate discriminative ability with a tendency to over-estimating risk rate. Continued efforts are needed to ensure external applicability of published nomograms by validating the program using an external patient population.

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