IBTR Risk Estimation

This application is a tool to estimate the risk of ipsilateral breast tumor recurrence (IBTR) after breast-conserving surgery. It provides 10-year IBTR risk estimates and treatment effects, based on clinicopathological factors (age, pathological T stage, grade, margin status, lymphovascular invasion, hormone receptor status, HER2 status) and treatment options (radiation therapy, chemotherapy, endocrine therapy, anti-HER2 therapy). The application is available for both iPhone and iPad.

The tool was developed using a Cox proportional hazards model from a multicenter cohort of 8,938 patients and calibrated with treatment effects from the EBCTCG meta-analysis. It is designed for use in shared decision-making between patients and clinicians, as well as for educational purposes. The development methodology was presented at the 2025 ASCO Annual Meeting (Abstract No. 575) and published in JCO Clinical Cancer Informatics (Sagara et al., 2025). For further details, please refer to the publication.

Disclaimer This application is intended for educational and informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be made in consultation with the treating physician. The developers assume no legal responsibility for any outcomes resulting from the use of this application.