Preoperative risk of positive surgical margins in breast-conserving surgery
This prediction tool calculates the estimated risk of positive surgical margins in T1-T2 breast cancer patients who consider breast-conserving surgery (c-index: 0.70).

The ability to estimate the preoperative risk of positive margins following lumpectomy could support clinicians in counseling patients regarding the likelihood of requiring further surgery, allowing for a more patient-tailored approach.
Research authors: Pleijhuis RG, Kwast AB, Jansen L, de Vries J, Lanting R, Bart J, Wiggers T, van Dam GM, Siesling S.
Version: 5.51
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Estimated risk of positive surgical margins:

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Conditional information

Overall model performance:
Model performance was validated on an external independent dataset (n=331) from the University Medical Center Groningen. Model calibration and discrimination were assessed graphically and by calculation of a concordance index, respectively. Concordance indices were calculated of 0.70 (95% CI: 0.66-0.74) and 0.69 (95% CI: 0.63-0.76) for the modeling and the validation group, respectively. Calibration of the model was considered adequate in both groups.

External model validation
In 2015, Barentsz et al. validated the model in their cohort of 576 Caucasian patients with non-palpable breast cancer from five hospitals. The authors reported a c-index of 0.617 (95% CI: 0.542-0.693). The authors mention that the difference in discriminative power might be related to differences in patient characteristics, as reflected by the difference in a priori probability of positive margins (21.4% vs. 12.0%). In addition, only non-palpable lesions were included in this study.

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This model is provided for educational, training and information purposes. It must not be used to support medical decision making, or to provide medical or diagnostic services. Read our full disclaimer.

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