THURSDAY, Aug. 30 (HealthDay News) -- Women with breast cancer who are treated with the cancer drug Herceptin may have more long-term cardiac problems than experts have thought, new research suggests.
It has been known that women treated with anti-cancer drugs known as anthracyclines and Herceptin (trastuzumab) are at higher risk for heart failure and cardiomyopathy, a weakening of the heart muscle.
But, that information on risks has come primarily from clinical trials, which typically exclude women aged 70 and older and those with co-existing chronic diseases, so it doesn't necessarily give a real-world picture, the researchers noted.
"The risk of heart failure associated with these drugs might be higher than what has been shown in clinical trials," explained study author Erin Aiello Bowles, an epidemiologist at Group Health Research Institute, in Seattle. Her report is published online Aug. 30 in the Journal of the National Cancer Institute.
Bowles and her colleagues evaluated 12,500 women diagnosed with invasive breast cancer from 1999 through 2007 in eight different health systems. The patients' average age was 60. The follow-up time ranged from more than two years to nearly seven.
The researchers used data from medical records and other sources to track type of cancer treatment and diagnoses of cardiac problems.
The risk of heart failure was 1.4 times higher in those treated only with an anthracycline at the five-year mark. That was about the same increase as those treated with other types of cancer drugs. However, those on Herceptin alone had more than four times the risk of heart problems compared to those who did not take the medication, the study stated.
And, the biggest increase in risk was seen in those on both anthracyclines and Herceptin. Those patients showed a sevenfold increased risk at the five-year mark, the researchers said.<
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