Attributable fraction of cardiac disease following radiotherapy among breast cancer survivors: a systematic review and meta-analysis.
Jeeyoung Lee, Eun Jung Park, Eria Bwogi et al.
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In 30 seconds
This systematic review and random-effects meta-analysis assessed the relationship between mean heart dose (MHD) from radiotherapy and cardiac disease among breast cancer survivors. Thirteen studies involving 16 446 survivors were included. Each 1 Gy increase in MHD was associated with a pooled relative risk of 1.09 (95% confidence interval, 1.05-1.13). At a representative MHD of 3.39 Gy, the estimated attributable fraction among irradiated patients was 24.3%; the population attributable fraction was 14.4%, assuming radiotherapy use of 52.7%.
Key findings
- The pooled relative risk of cardiac disease was 1.09 (95% confidence interval, 1.05-1.13) per Gy increase in mean heart dose.
- At a representative mean heart dose of 3.39 Gy, the estimated attributable fraction among irradiated patients was 24.3%.
- With radiotherapy utilization of 52.7%, the estimated population attributable fraction among breast cancer survivors was 14.4%.
- From before 2000 to thereafter, mean heart dose fell from 7.03 Gy to 2.57 Gy and the population attributable fraction from 24.5% to 13.2%.
Why it matters
The findings quantify a continuing cardiac disease burden associated with heart exposure during breast cancer radiotherapy, even as mean heart dose has declined. They support attention to cardiac dose as part of treatment planning and survivorship care, while the attributable fractions remain estimates derived from pooled dose-response data and representative exposure assumptions.
What to keep in mind
Attributable fractions were estimated using pooled dose-response coefficients and representative mean heart doses and radiotherapy utilization, rather than measured directly across all survivors.