Background

Radiotherapy halves the recurrence risk and reduces breast cancer death after breast sparing surgery, but it is associated cardiac morbidity and mortality (1). The EBCTCG data demonstrates an excess cardiac mortality rate ratio of 4,1% per increased Gray (Gy) whole heart dose (2). The aim of this study is to create a clinical applicable risk assessment model to predict 10-year cardiovascular mortality in female breast cancer patients.

Methods

By integration of the SCORE (Systematic COronary Risk Evaluation) risk charts and data of the EBCTCG we were able to develop cardiovascular mortality risk charts based on mean heart dose, age, systolic blood pressure, smoking-status and cholesterol for high- and low-risk regions in Europe, for contemporary mean heart doses of 2Gy, 4Gy and 8Gy.

Results

We will present tables showing the 10-year cardiovascular mortality based on mean heart dose, smoking status, age, systolic blood pressure and cholesterol for high- and low-risk regions in Europe. Below you find the risk table for 60-years old non-smoking women in low-risk regions. A 60-year old, non-smoking patient from France (low-risk region) with a cholesterol 220 mg/dl and a systolic blood pressure of 140 mmHg has a 10-year cardiovascular mortality risk of 1,0%, adding radiotherapy with a mean heart dose of 4Gy will increase it to 1,1% and doubling the heart dose to 8Gy results in a risk of 1,2%. In contrast, a 65 year old smoking patient living in Bosnia (high-risk region) with a cholesterol of 260 and a systolic blood pressure of 160 mmHg has a 10-year cardiovascular mortality risk of 13,0%, adding radiotherapy with a mean heart dose of 4Gy will increase it to 14,3% and doubling the heart dose to 8Gy results in a risk of 15,7%.Table:

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Conclusions

Integrating cardiovascular risk tables and radiotherapy data are useful for patient individualized radiotherapy and cardiovascular prevention after breast cancer treatment. (1) Lancet 2011;378(9804):1707-16. (2) J Clin Oncol 2017;35(15):1641-1649.

Legal entity responsible for the study

The authors.

Funding

Vrije Universiteit Brussel.

Disclosure

All authors have declared no conflicts of interest.