Breast Cancer Chemotherapy Increases Heart Damage Risk

NEW YORK JAN 05, 2006 (Reuters Health) - Chemotherapy, especially anthracycline-based therapy, for breast cancer in older women increases their risk of developing cardiomyopathy.

Doxorubicin and other chemotherapeutic agents are increasingly used in the adjuvant chemotherapy of breast cancer patients, the authors explain, but long-term sequelae in such patients have received little attention.

Dr. Dawn L. Hershman from Columbia University, New York City and colleagues evaluated chemotherapy use and cardiotoxicity among 5575 women 65 years old or older in the general population diagnosed with stage I or II breast cancer.

Increasing age and black race were associated with higher rates of heart disease in these patients, the authors report, and patients with heart disease before the breast cancer diagnosis were 2.4 times more likely to experience heart disease during follow-up.

After adjusting for these factors, women who received chemotherapy had a 22% increase in the rate of heart disease, a 55% increase in the rate of cardiomyopathy, and a 20% increase in the rate of congestive heart failure, the report indicates.

The combination of radiation therapy and chemotherapy was associated with a slightly higher risk of heart disease (33%), the researchers report in the December 1st issue of the Journal of Clinical Oncology.

Among the chemotherapeutic agents used, doxorubicin was associated with the greatest increase in cardiomyopathy risk (2.5-fold), the results indicate.  The incidence of cardiomyopathy in the first year after diagnosis ranged from 1.55% for women who didn"t receive chemotherapy to 4.09% for women who received doxorubicin, the investigators observe.

"The elevated risk of cardiac disease associated with adjuvant chemotherapy, which has been observed among participants in clinical trials, is also present among elderly breast cancer patients in a population-based sample," the authors conclude. "Given the prevalence of anthracycline regimens in the current adjuvant breast cancer setting, some patients may benefit from increased cardiac monitoring."

SOURCE:

• J Clin Oncol 2005;23:8597-8605.