Myocardial Infarction risk for women with breast cancer

Myocardial Infarction Risk for Women with Breast Cancer: Annotated Bibliography
Abdel-Qadir, H., Amir, E., Fischer, H. D., Fu, L., Austin, P. C., Harvey, P. J., ... & Anderson, G. M. (2016). The risk of myocardial infarction with aromatase inhibitors relative to tamoxifen in post-menopausal women with early stage breast cancer. European Journal of Cancer, 68, 11-21.
The rationale for this study was that a gap in the literature existed with respect to the possibility of aromatase inhibitors increasing cardiovascular risk relative to tamoxifen among breast cancer patients who were in the post-menopause phase of life. The participants consisted of more 9500 women over the age of 55 suffering from breast cancer (stage 1 to 3) in Ontario, Canada. The researchers conducted an observational cohort study to observe the myocardial infarction risk of aromatase inhibitors and tamoxifen. They examined cases of hospitalization of the population sampled as a result of myocardial infarction and compared cases of those being treated with aromatase inhibitors to those being treated with tamoxifen.
The researchers found that aromatase inhibitors were associated with higher risk of myocardial infarction compared to risk associated with tamoxifen. The implications for clinical practice are that nurses and physicians should consider restricting treatment of breast cancer in post-menopausal women to tamoxifen and not use aromatase inhibitors such as Arimidex, Aromasin or Femara as these can raise the risk of myocardial infarction. Reduction of aromatase inhibitors could help to lower the rate of hospitalization for myocardial infarction for this particular population as well.
Cheng, Y. J., Nie, X. Y., Ji, C. C., Lin, X. X., Liu, L. J., Chen, X. M., ... & Wu, S. H. (2017). Long?Term Cardiovascular Risk After Radiotherapy in Women With Breast Cancer. Journal of the American Heart Association, 6(5), e005633.
The rationale for this study was to obtain quantitative data that could provide an indication as to whether or not there was a link between radiotherapy for breast cancer and the risk of heart disease. The researchers wanted to fill a gap in the literature pertaining to quantified data on heart disease risk and ionizing radiation. No experiment or test was conducted and no participants were used in this study. Instead, the researchers conducted a systematic literature review and meta-analysis. The researchers examined 39 studies and obtained their data from there, looking at studies that focused on radiotherapy and that included information about the effects of this intervention on the heart. They summarized the statistical evidence accumulated through this review, identifying what all the different studies found.
The researchers found that the evidence as reported in the literature review indicated a strong association between radiotherapy and the risk of heart disease. According to the studies reviewed, patients who received radiotherapy were statistically more at risk of developing heart disease than patients who did not. The implications for practice are that physicians should consider the risk/reward ratio when it comes to using radiotherapy as an intervention for treating breast cancer. It may help to defeat the cancer but it can have long-term negative side effects on the condition of the heart. These side effects can include an increased risk for coronary heart disease and cardiac death. To ensure the total safety of the patient, alternatives to radiotherapy should be considered, and patients should be educated about the risks that come with the radiotherapy intervention.
Darby, S. C., Ewertz, M., McGale, P., Bennet, A. M., Blom-Goldman, U., Brønnum, D.,... & Jensen, M. B. (2013). Risk of ischemic heart disease in women after radiotherapy for breast cancer. New England Journal of Medicine, 368(11), 987-998.
The rationale for this study was that uncertainty existed about whether radiation in the treatment of breast cancer increased the risk of ischemic heart disease in the patients. The concern stemmed from awareness that incidental exposure of the heart to radiation during the treatment process was likely to occur. The researchers wanted to obtain quantifiable data to shed light on this issue and better determine whether patients who received radiation therapy for breast cancer were indeed at greater risk of developing heart disease. The participants for this study included over 2100 women who received breast cancer radiation therapy in the Nordic states in Europe between the years of 1958 and 2001. The study was a case-control design and patient data was obtained from hospital records and radiation exposure was obtained from the patients’ charts.
The researchers found that exposure of the heart to radiation did increase the risk of the patient developing heart disease long-term. They found a direct proportional correlation between the radiation dosage that the heart was incidentally exposed to and the rate of cardiac disease development. The researchers also found that patients who were already predisposed to cardiac risk factors had greater prevalence of cardiac disease over time. This indicates that radiation therapy is likely one risk factor in the onset of cardiac disease but most likely not the only one. The implications for clinical practice are that nurses and physicians should be mindful of explaining to breast cancer patients the risks of radiation therapy on the heart. Though this study’s findings were not corroborated by the findings of James et al. (2018), these researchers did use a larger sample size than the study conducted by James et al. and therefore there may be greater reliability in this study than in the one conducted by James et al.
James, M., Swadi, S., Yi, M., Johansson, L., Robinson, B., & Dixit, A. (2018). Ischaemic heart disease following conventional and hypofractionated radiation treatment in a contemporary breast cancer series. Journal of medical imaging and radiation oncology.
The rationale for this study was to examine patients to see if there was a significant relation between breast cancer radiation treatment and cardiac disease or death. More than 500 patients were participants in this study, all of whom received external beam radiation treatment between the years of 2002 and 2006 at Christchurch hospital. The researchers examined the number of instances of cardiac death and cardiac event over a 10 year period following the radiation intervention.
The finding of the study was that there was low risk of cardiac disease developing in women who were treated for breast cancer by way of radiation. This finding contradicts the finding of Cheng et al. (2017). The sample size of 500 participants is suitably large to have significance, but part of the problem that the researchers found was that cardiac risk factors were already common among the population, which consisted of women over the age of 55. In other words, the researchers could not rule out other factors as having more of an effect on the heart than the radiation therapy. The researchers concluded that radiation may have some risk in terms of causing cardiac disease but that risk is low—and there are many other risks as well that the participants already appeared to be dealing with. The implication for practice from this study is that care providers should discuss the risk of radiation therapy on the heart but that they should also point out that there are many other factors that can negatively impact the heart as well—such as diet, exercise, smoking, drinking, and so on. This would provide patients with a much clearer sense of the risk vs. reward situation when it comes to radiation therapy.
Jones, L. W., Habel, L. A., Weltzien, E., Castillo, A., Gupta, D., Kroenke, C. H., ... & Yu, A. (2016). Exercise and risk of cardiovascular events in women with nonmetastatic breast cancer. Journal of Clinical Oncology, 34(23), 2743.
The rationale for this study was that women with breast cancer commonly die from cardiovascular disease, which is one of the leading causes of death for this population. The researchers wanted to know whether exercise would help to reduce the risk of cardiovascular disease in this population. As the connection between exercise and cardiovascular risk reduction for this population was unknown, the researchers aimed to fill the gap by conducting a survey of nearly 3000 women with breast cancer. The purpose of the survey was to identify the relationship of the variables exercise and cardiovascular disease occurrence in the population.
The researchers found that when women with breast cancer adhered to an exercise regime that was up to the national exercise standards for adult women, their risk of developing cardiovascular disease was reduced substantially. The implications for practice of this finding is that physicians and nurses should stress to patients with breast cancer the importance of exercising regularly, as this population is already at an elevated risk for cardiovascular disease. Exercise can help bring that risk level down and potentially provide patients with a higher quality of life.