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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}
}
  • Purpose: To compare outcomes of salvage mastectomy (SM) and salvage breast-conserving surgery (SBCS) and study the feasibility of SBCS. Methods and Materials: Of 2,038 patients treated with breast-conserving therapy at Yale-New Haven Hospital before 1999, 166 sustained an ipsilateral breast tumor recurrence (IBTR). Outcomes and prognostic factors of patients treated with SM or SBCS were compared. Patients were considered amenable to SBCS if the recurrence was localized on mammogram and physical examination, and had pathologic size <3 cm, confined to the biopsy site, without skin or lymphovascular invasion, and with {<=}3 positive nodes. Results: Of the 146 patients definitively managedmore » at IBTR, surgery was SM (n = 116) or SBCS (n 30). The median length of follow-up after IBTR was 13.8 years. The SM and SBCS cohorts had no significant differences, except at IBTR the SM cohort had a greater tumor size (p = 0.049). Of the SM cohort, 65.5% were considered appropriate for SBCS, and a localized relapse was predicted by estrogen-receptor positive, diploid, and detection of recurrence by mammogram. Multicentric disease correlated with BRCA1/2 mutation, estrogen-receptor negative, lymph node positive at relapse, and detection of recurrence by physical examination. Survival after IBTR was 64.5% at 10 years, with no significant difference between SM (65.7%) and SBCS (58.0%). Only 2 patients in the SBCS cohort subsequently had a second IBTR, and were salvaged with mastectomy. Conclusions: While mastectomy is considered the standard surgical salvage of IBTR, SBCS is feasible and prognostic factors are related to favorable tumor biology and early detection. Patients with BRCA1/2 germline mutations may be less appropriate for SBCS, as multicentric disease was more prevalent. Patients who underwent SBCS had comparable outcomes as those who underwent SM, but remain at continued risk for IBTR. A prospective trial evaluating repeat lumpectomy and partial breast reirradiation is discussed.« less
  • Purpose: Ipsilateral breast tumor recurrence (IBTR) can occur in 5-20% of women with early-stage breast cancer treated with breast-conserving therapy. Two entities of IBTR have been described: true recurrence (TR), suggested to be regrowth of disease at the tumor bed, and new primary (NP), distinct from the index lesion in histology and location. This study compared survival outcomes between two patient cohorts classified clinically as having either TR or NP. Methods and Materials: Between 1989 and 1999, 6,020 women were referred to the BC Cancer Agency with newly diagnosed pT1-2, N0-1, M0 invasive breast cancer, treated with breast-conserving surgery. Ofmore » these, 289 patients had pathologically confirmed IBTR. Retrospective analysis was performed, and a set of decision rules was applied to classify cases as TR or NP based on change in histology, grade, hormone receptor status, and tumor location. Of 289 patients, 129 (45%) were classified as having TR and 139 (48%) as having NP; 21 (7%) were unclassified. Results: The distributions of age at diagnosis, age at recurrence, and histopathologic factors were similar in the TR and NP cohorts (all p > 0.05). The mean time to recurrence was shorter in TR patients than in NP patients (4.8 years vs. 6.3 years, p = 0.001). Treatment of the IBTR did not differ between the two groups. In the TR and NP cohorts, breast cancer-specific survival was 55.7% vs. 61.3% (p = 0.93), and overall survival was 43.7% vs. 54.8% (p = 0.53). Conclusions: Time to recurrence is significantly shorter in patients with IBTR classified as true recurrence compared to new primary. Non-statistically significant trends for less favorable survival were observed for patients with TR. Further investigation of the hypothesis that TR and NP tumors are distinct entities with different survival prognoses will require standardized pathology review and molecular analyses.« less
  • Purpose: To analyze the incidence and prognostic factors of ipsilateral breast tumor recurrence (IBTR) after breast-conserving therapy (BCT) in a large, population-based, single-center study with long-term follow-up. Methods and Materials: We analyzed 3595 cases in which BCT was performed in 3824 women with stage I or II breast cancer. The incidence of IBTR was analyzed over time and was based on IBTR as first event. Results: The 15-year local relapse-free survival was 90.9%. The hazard estimates for IBTR showed a time course with 2 peaks, the first at approximately 5 years and the second, twice as high, at 12 years. Stratifying subjectsmore » by age and margin status showed that, for women ≤40 years old with negative margins, adjuvant systemic therapy led to a 5-fold reduced risk of recurrence compared to none, and the presence of lymph vascular space invasion (LVSI) had a 3-fold increased risk compared to its absence. For women >40 years old, the presence of LVSI (hazard ratio [HR] 2.5) and the presence of lobular carcinoma in situ in the lumpectomy specimen (HR 2.3) were the only 2 risk factors. Conclusions: We demonstrated a pattern in risk of IBTR over time, with 2 peaks, first at approximately 5 years and a second, much higher peak at approximately 12 years, especially for women ≤40 years old. For women ≤40 years old with tumor-free resection margins, we noted that the absence of adjuvant systemic therapy and the presence of LVSI were independent prognostic factors of IBTR. For women >40 years old, the presence of LVSI and the presence of lobular carcinoma in situ were independent risk factors.« less
  • Purpose: The aim of this study was to evaluate the clinical outcome of breast conservation therapy (BCT) for invasive breast cancers in our predominantly Chinese population. Methods and Materials: Clinical outcomes of 412 T1-2 invasive breast cancers treated by wide local excision and external radiotherapy from 1994 to 2003 were retrospectively analyzed. Only 7% lesions were first detected by mammograms. Adjuvant tamoxifen and chemotherapy were added in 74% and 45% patients, respectively. Results: The median follow-up was 5.4 years. The 5-year actuarial ipsilateral breast tumor recurrence (IBTR) rate, distant failure-free survival, cause-specific survival, and overall survival were 4%, 92%, 96%,more » and 98%, respectively. The 5-year distant failure-free survival for the low-risk, intermediate-risk, and high-risk categories (2005 St. Gallen) were 98%, 91%, and 80%, respectively (p 0.0003). Cosmetic results were good to excellent in more than 90% of the assessable patients. Grade 3 histology (hazard ratio [HR], 4.461; 95% CI, 1.216-16.360; p = 0.024), age (HR, 0.915; 95% CI, 0.846-0.990; p = 0.027), and close/positive final margins (HR, 3.499; 95% CI, 1.141-10.729; p = 0.028) were significant independent risk factors for IBTR. Both St. Gallen risk categories (p = 0.003) and IBTR (HR, 5.885; 95% CI, 2.494-13.889; p < 0.0005) were independent prognostic factors for distant failure-free survival. Conclusions: Despite the low percentage of mammographically detected lesions, the overall clinical outcome of BCT for invasive breast cancers in the Chinese population is comparable to the Western series. The 2005 St. Gallen risk category is a promising clinical tool, but further validation by large studies is warranted.« less
  • Background: It is generally believed that ipsilateral breast failures (IBFs) after breast-conserving therapy (BCT) develop from incompletely eradicated carcinoma. We previously suggested that monomorphic epithelial proliferations (MEPs) in the breast may be a pool of partially transformed clones from which breast carcinomas can arise and that radiation therapy (RT) may also reduce the risk of IBF by eradicating MEPs. We examined salvage mastectomy specimens in patients experiencing an IBF to define the relationship between MEPs and IBFs and an additional potential mechanism for IBF risk reduction by RT. Methods and Materials: The location, number, and distribution of radiation changes andmore » MEPs relative to 51 IBFs were mapped in salvage mastectomy specimens from BCT patients with adequately excised, initial carcinomas (negative lumpectomy margins). Results: All 51 salvage mastectomies had diffuse, late radiation changes. None had active fibrocystic lesions. MEPs were predominantly located in the immediate vicinity of the IBFs. A mean of 39% of MEP cases were located within the IBF, 46% were located within 2 cm of the IBF, and 14% were 2-3 cm from the IBF. Conclusions: MEPs appear to be a pool of partially transformed precursor lesions that can give rise to ductal carcinoma in situ and invasive carcinomas (CAs). Many IBFs may arise from MEPs that reemerge after RT. Radiation may also reduce IBF risk after BCT (including in patients with negative margins) by primarily eradicating MEPs.« less