Validation cohort from the University Medical Center Groningen
Study population:
This external validation group consisted of 439 patients who underwent BCT at the University Medical Center Groningen (UMCG), Groningen, The Netherlands between July 2004 and June 2008 or July 2009 and May 2011. A total of 331 patients (75%) were eligible for analysis.

Inclusion criteria: 
Women with clinical T1–2N0–1Mx–0 histology-proven invasive breast carcinoma who underwent BCT were included in the study.

Exclusion criteria: 
Patients with unconfirmed malignancy prior to surgery, undefined margin status, neo-adjuvant treatment, or absence of reported radiological tumor size were excluded. 
 
Validation study authors: Pleijhuis RG
Validation author
Revision date
2018-06-24
MeSH terms
  • Breast Cancer
  • Breast Carcinoma
  • Breast-Conserving Surgery
  • Surgery, Breast-Conserving
  • Status
    public
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    Details

    Related files

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    Supporting Publications

    No supporting publications available

    Discrimination

    C-index: 0.6895 | 95% CI: 0.6207 - 0.7582
    ROC Plot:

    Calibration

    Regression coefficient: 1.2211 | Intercept: 0.05
    Calibration plot:

    Histogram

    Rows included: 331
    Comparison
    Original study population: 1185
    Validation study population: 331

    Categorical characteristics

    Name Subset / Group Nr. of patients Validation P-Value
    Age <40 years 39 28 0.0005
    40-70 years 919 255
    >70 years 227 48
    Tumor size pT1a 54 22 0.096
    pT1b 243 81
    pT1c 599 164
    pT2 284 62
    pT3 5 2
    Area on mammogram <15.000 mm2 450 138 0.3558
    15.000-25.000 mm2 554 142
    >25.000 mm2 181 45
    Weight excised <50 gram 270 167 0.1434
    50-100 gram 172 78
    >100 gram 165 82
    Tumor-to-lump index <0.25 278 121 0.1209
    0.25-0.50 228 135
    >0.50 101 53
    Palpability Palpable 637 195 0.1043
    Non-palpable 548 136
    Tumor location LOQ 122 42 0.0005
    UOQ 535 170
    UIQ 189 50
    LIQ 150 26
    Central 103 6
    Histological type Ductal 957 286 0.061
    Lobular 119 23
    Specified 109 22
    Histological grade Grade I 330 107 0.1999
    Grade II 531 133
    Grade III 313 86
    ER status Positive 1002 276 0.661
    Negative 172 51
    PR status Positive 750 226 0.4434
    Negative 300 101
    Her2/neu receptor status Positive 125 40 0.4862
    Negative 1041 290
    Multifocal disease Yes 47 19 0.1707
    No 1138 312
    pN-stage Positive 310 113 0.0055
    Negative 875 218
    Prior surgery to the breast Yes 46 34 < 0.0001
    No 1139 297
    Family history FDR 91 75 0.0005
    SDR 188 56
    Negative 749 199
    BI-RADS classification II 3 8 0.001
    III 93 31
    IV 611 155
    V 447 127
    Preoperative MRI Yes 122 31 0.6803
    No 1063 300
    Microcalcifications Yes 245 74 0.5421
    No 937 257
    DCIS component present Yes 529 188 0.0001
    No 656 143
    Breast density 0-25% 323 101 0.8061
    25-50% 467 146
    50-75% 217 70
    75-100% 34 7
    Institution University-affiliated 642 331 < 0.0001
    Community hospital 543 0

    Continuous characteristics

    Name Mean SD Unit Plot
    Original
    Validation
    Age 59.8
    56.5
    0.31
    0.63
    years
    Original
    Validation
    Tumor size 15.6
    15.2
    0.22
    0.48
    mm
    Original
    Validation
    Area on mammogram 17916
    17575
    6807
    6937
    mm2
    Original
    Validation
    Weight excised lump 62.5
    56.3
    39.7
    40.0
    gram
    Original
    Validation
    Tumor-to-lump index 0.338
    0.354
    0.012
    0.020
    (index)
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