Chemotherapy and Cardiovascular Diseases

Thanks to modern medicine, more people are surviving cancer today than ever. Sadly, heart disease is the leading cause of death among cancer survivors (1). Risk of cardiovascular disease in cancer survivors has been linked to the use of chemotherapy medications, such as anthracyclines. Anthracyclines are among the commonly used medications for the treatment of  breast cancer and childhood cancers. While they are excellent at treating cancer, they are associated increased risk for heart failure (2).  In fact, in the Childhood Cancer Survivor Study, which examined 14,358 survivors of childhood cancers, those who had been treated with these medications (anthracyclines) were 2.4 times more likely to experience heart failure than those who did not receive anthracyclines (1).

Heart disease from anthracyclines is caused by death to the cardiomyocytes, or the cardiac muscle cells. Anthracyclines can damage cardiac cells by producing different toxic chemicals. These medications are developed to kill cancer cells by damaging DNA. As the body metabolizes the anthracyclines, like it does the food we eat, by-products are released. These by-products take the form toxic chemicals called reactive oxygen species (ROS) (1). These toxic compounds can lead to damage and heart cell death. As the heart cells get damaged and slowly die, heart function is compromised, which may result in heart failure.  So while chemotherapy is great at curing cancer, it can also damage the heart, one of the most important organs in the human body.

Life after Chemotherapy

Chemotherapy with anthracyclines can lead to early and late damage to the heart, which can lead to a decline of blood-pumping ability in the heart, shortness of breath, fatigue and swelling of legs (3). Any cancer patient who is planning to receive anthracycline-based chemotherapy should have optimal evaluation of cardiovascular risk factors prior to this chemotherapy exposure. There are multiple interventions that can be done to minimize the risk of cardiovascular disease, including management of high blood pressure, pre-existing heart failure, and other cardiac conditions. All patients who are planning to receive chemotherapy should receive a baseline clinical cardiovascular assessment. A repeat assessment with clinical history and examination at least every three months should be performed by a clinician during the treatment course (4).

Addressing cancer-treatment-related heart disease in cancer survivors is not a simple task. Cancer survivors may develop post traumatic stress disorder (PTSD), depression, anxiety, and other forms of mental illnesses including substance abuse disorders. In addition, it is important to remember that cancer survivors are often left with debilitating side effects from the treatment. Research has shown that chemotherapy can lead directly to cognitive deficiencies such as problems with attention, memory and daily functioning (5). Cancer survivors often refer to problems of thinking and memory as “chemo-brain” or “chemo-fog.” This can be frustrating and debilitating for the day-to-day functioning of the cancer patient.

Intervention and Conclusion

There is scientific evidence that links negative emotional states, such as depression, anxiety, or anger, to an increased risk for cardiovascular disease (6). In fact, one large population-based study was able to show that an outwardly displayed positive outlook on life was protective against 10-year incident coronary heart disease (CHD) (7). Thus, behavioral interventions that increase quality of life overall, both increasing positive effects and decreasing negative effects, may actually be an effective way to protect against CHD.

Finally, it is important to remember that surviving cancer does not necessarily translate into good health. Cancer survivors are significantly more likely than the average person to report being in fair or poor health, having a psychological disability, being limited in activities of daily living, and having functional struggles (8). A study found that compared with the general population, cancer survivors consumed more empty calories in the form of solid fats, alcohol, and added sugars (9). Many cancer survivors also smoke. These behaviors and conditions, in conjunction with the side-effects from cardiotoxic chemotherapies such as those that utilize anthracyclines, can further increase the risk of heart disease and other medical complications for this very at-risk population.

The number of cancer survivors in the United States is on the rise and it is likely that there will be an increase in the prevalence of cardiovascular disease resulting from cancer-related therapies. It is of great importance that public health professionals and clinicians continue to find innovative and adaptive methods to protect the cardiovascular health of people suffering from cancer or in chemotherapy.

References:

(1) Volkova M, Russell R. Anthracycline cardiotoxicity: prevalence, pathogenesis and treatment. Curr Cardiol Rev. 2011;7(4):214-20.

(2) Daher IN, Daigle TR, Bhatia N, Durand JB. The prevention of cardiovascular disease in cancer survivors. Tex Heart Inst J. 2012;39(2):190-8.

(3) Singal PK, Iliskovic N. Doxorubicin-induced cardiomyopathy. N Engl J Med. 1998;339(13):900.

(4) Khouri MG, Douglas PS, Mackey JR, Martin M, Scott JM, Scherrer-Crosbie M, Jones LW. Cancer therapy-induced cardiac toxicity in early breast cancer: addressing the unresolved issues. Circulation. 2012 Dec;126(23):2749-63.

(5) Vichaya EG, Chiu GS, Krukowski K, Lacourt TE, Kavelaars A, Dantzer R, Heijnen CJ, Walker AK.(2015). Mechanisms of chemotherapy-induced behavioral toxicities. Front Neurosci. 2015 Apr 21;9:131. doi: 10.3389/fnins.2015.00131

(6) Sugawara, J., Tarumi, T., & Tanaka, H. (2010). Effect of mirthful laughter on vascular function. Am J Cardiol, 106(6), 856-859. doi: 10.1016/j.amjcard.2010.05.011

(7) Davidson, K. W., Mostofsky, E., & Whang, W. (2010). Don’t worry, be happy: positive affect and reduced 10-year incident coronary heart disease: the Canadian Nova Scotia Health Survey. European Heart Journal, 31(9), 1065-1070. doi: 10.1093/eurheartj/ehp603

(8) Hewitt M, Rowland JH, Yancik R. Cancer survivors in the United States: age, health, and disability. J Gerontol A Biol Sci Med Sci. 2003;58(1):82-91.

(9) Zhang FF, Liu S, John EM, Must A, Demark-wahnefried W. Diet quality of cancer survivors and noncancer individuals: Results from a national survey. Cancer. 2015;121(23):4212-21.

 

 

 

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