Long-term cardiovascular mortality after radiotherapy for breast cancer: A systematic review and meta-analysis

Clin Cardiol. 2017 Feb;40(2):73-81. doi: 10.1002/clc.22631. Epub 2016 Nov 2.


Background: Radiotherapy (RT) is frequently associated with late cardiovascular (CV) complications. The mean cardiac dose from irradiation of a left-sided breast cancer is much higher than that for a right-sided breast cancer. However, data is limited on the long-term risks of RT on CV mortality.

Hypothesis: RT for breast cancer is associated with long term CV mortality and left sided RT carries a greater mortality than right sided RT.

Methods: We searched PubMed, Cochrane Central, Embase, EBSCO, Web of Science, and CINAHL databases from inception through December 2015. Studies reporting CV mortality with RT for left- vs right-sided breast cancers were included. The principal outcome of interest was CV mortality. We calculated summary risk ratio (RR) and 95% confidence intervals (CI) with the random-effects model.

Results: The analysis included 289 109 patients from 13 observational studies. Women who had received RT for left-sided breast cancer had a higher risk of CV death than those who received RT for a right-sided breast cancer (RR: 1.12, 95% CI: 1.07-1.18, P < 0.001; number needed to harm: 353). Difference in CV mortality between left- vs right-sided breast RT was more apparent after 15 years of follow-up (RR: 1.23, 95% CI: 1.08-1.41, P < 0.001; number needed to harm: 95).

Conclusions: CV mortality from left-sided RT was significantly higher compared with right-sided RT for breast cancer and was more apparent after ≥15 years of follow-up.

Keywords: Breast Cancer; Cardiovascular Mortality; Radiotherapy.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Breast Neoplasms / radiotherapy*
  • Cardiovascular Diseases / etiology
  • Cardiovascular Diseases / mortality*
  • Dose-Response Relationship, Radiation
  • Female
  • Forecasting*
  • Global Health
  • Humans
  • Incidence
  • Radiation Injuries / complications*
  • Radiation Injuries / epidemiology
  • Radiotherapy, Adjuvant / adverse effects
  • Risk Factors
  • Survival Rate / trends