According to a new Cancer Research Network study by Group Health researchers and others, published in the Journal of the National Cancer Institute, women who have breast cancer and receive 2 chemotherapy drugs may experience more cardiac problems as a result of treatment.
Often the cure for breast cancer is problematic, as shown in this study when chemotherapy leads to other health problems. Lead author Erin Aiello Bowles, MPH, an epidemiologist at Group Health Research Institute, said the study is significant because more and more women are surviving longer with breast cancer, so it’s becoming a chronic disease.
Ms Bowles and her colleagues estimated real-world use of anthracycline and trastuzumab and then studied the drugs’ associations with heart failure and cardiomyopathy. Although earlier clinical trials show that women treated for breast cancer with the drugs anthracycline or trastuzumab are at increased risk for heart failure, cardiomyopathy, or both, these clinical trials excluded large categories of patients, including elderly women and those with other health problems, such as existing heart disease. Therefore, the limitations of the previous studies may mistake what occurs in the general population.
“We tried to take a broader look by estimating the risk of heart failure in a more general population,” Ms Bowles said. “We looked at all the women in a population with breast cancer, not selected ones. Our study shows that people who are not generally eligible for clinical trials – older women and those with existing heart failure – do receive these drugs in real life.”
In the retrospective, population-based cohort study of 12,500 women diagnosed with invasive breast cancer, the overall risk of developing either heart failure or cardiomyopathy was significantly higher in women treated with anthracycline alone compared with no chemotherapy. However, among women who used trastuzumab alone, the overall risk of these cardiac problems was even greater. For women who used both anthracycline and trastuzumab, the risk was greater than previously reported. Furthermore, researchers discovered that women receiving anthracycline (with or without trastuzumab) were often younger and without other illnesses, while women on trastuzumab alone tended to be older and have more illnesses.
Ms Bowles added, “These drugs are toxic. They kill cancer cells, and sometimes kill other cells in the body, too. These drugs are still important for women with breast cancer to use because we know they improve survival. But as with any drug, people need to be aware of the risks, too.”
Source: Group Health.
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