Breast cancer does not pose increased heart-specific mortality
Breast cancer survivors do not have higher heart-specific mortality compared with the general population, a study has found.
Researchers followed 501,547 patients (mean age at diagnosis, 59.94 years), among whom 347,476 received treatment with either chemotherapy or radiotherapy, to investigate long-term heart-specific mortality. Compared with patients who did not receive radiotherapy or chemotherapy, treated patients were on average younger at diagnosis, rather diagnosed in later stages and with higher gradings.
The median follow-up was 8.4 years in the treated group vs 8.6 years in the untreated group. Breast cancer comprised the highest cumulative mortality among all possible competing causes of death. Compared with the general population, breast cancer patients who received radiotherapy or chemotherapy had lower heart-specific mortality (standardized mortality ratio, 0.84; 95 percent CI, 0.79–0.90).
Subgroup analysis showed that human epidermal growth factor receptor 2 (HER2)-positive subtype was not associated with increased heart-specific mortality relative to HER2-negative breast cancer (hazard ratio [HR], 0.96; 0.70–1.32).
Among breast cancer patients, heart-specific mortality increased with age, with HRs of 1.89, 5.98 and 22.78 in the 55–64, 65–74 and ≥75 years age groups vs the 50–54 age group, respectively. Heart-specific mortality was also associated with stage, even though the association was less pronounced than for breast cancer mortality (stage IV vs I: HR, 2.90; 2.43–3.46).
Finally, compared with white patients, black patients were at higher risk of heart-specific death (HR, 1.85; 1.72–1.99), whereas Asian/Pacific islander patients were at lower risk (HR, 0.74; 0.65–0.84).
Additional studies with more detailed data on treatment are warranted to validate the present data and further examine potential prognostic factors, researchers said. These might aid in further development of cardio-oncological risk stratification among breast cancer patients and help clinicians make informed decisions regarding which patient strata are at highest risk and who would benefit most from preventive interventions.