with RT
w/o RT
IBTR! Version 2.0
Breast Cancer Model

This program is designed for use by physicians to guide medical decision-making regarding the use of radiation therapy in breast cancer patients who have undergone breast conserving surgery and appropriate axillary evaluation. This model calculates an evidence-based estimate of the 10-year ipsilateral breast tumor recurrence risk with and without the addition of whole breast radiation therapy.

This program is not intended for use in the post-mastectomy setting, and it is not meant to address patients with multicentric disease or with in-situ only disease. It is assumed that all pathological specimens have been microscopically assessed with current histopathological standards. It is presumed that patients who are lymph node positive (with the exception of micrometastatic lymph node disease) will receive systemic therapy, either chemotherapy or hormonal therapy. The calculated benefit of hormonal therapy in this model is based on the tamoxifen literature and has been extrapolated to the use of aromatase inhibitors. Recent studies indicate that aromatase inhibitors have a similar, and possibly a slightly superior, impact on local control.

The arm of the IBTR! nomogram that calculates local recurrence risk with radiation has undergone rigorous validation testing with collaboration of two large institutional datasets. This publication has been accepted by a major peer reviewed journal and will be in print shortly. The calculation of local recurrence risk without radiation has not been validated because of unavailability of a large diverse cohort of patients that did not receive radiation therapy. Therefore the predicted recurrence risk without radiation therapy is based on the consistent relative risk reduction of 0.7 seen across multiple randomized trials with the use of breast irradiation

This model should only be used by physicians who are familiar with the complexity of treatment decisions in breast cancer and should not be used directly by patients. Any decisions made regarding the use of adjuvant breast irradiation should be based on the treating physician’s clinical judgement, with the model output supplementing but not substituting for this individual clinical assessment. The creators of IBTR! are not liable for clinical decision making that occurs between a physician and patient

By proceeding with use of this nomogram, the user agrees that they have read and agreed with these terms.

Tumor Size:
Tumor Grade:
Margin Status:
Lymphovascular Invasion:
Tamoxifen/Aromatase Inhibitor:

10-Year Risk of Ipsilateral Breast Tumor Recurrence
With Radiation Therapy:
Without Radiation Therapy: