Breast cancer is commonly treated with chemotherapy, which are medications used to weaken and kill the cancer cells. Since chemotherapy works systemically, meaning throughout the body, it can kill the cancer cells both at the original tumor site as well as any cells that have spread. Many of the chemotherapy drugs used to treat breast cancer are very potent and can cause damage to healthy cells and organs in the body, including the heart.
Irregular Heart Beat
Taxol, a chemotherapy medication commonly used to treat breast cancer, induces an irregular heart beat in three percent of patients. Some women experience a slow heartbeat known as bradycardia, while others just notice the irregular heartbeat known as arrhythmia. This effect may be even more pronounced in women receiving combination chemotherapies.
Chest Pain
Chest pain is a side effect felt with breast cancer, but it is not always due to the chemotherapy. The pain can be caused by nerve damage from surgery or radiation treatments. Several chemotherapy medications however can affect the heart so it is important to talk to your doctor about all symptoms especially chest pain since it can be a sign of heart attack.
Heart Failure
Medications used to treat breast cancer, such as trastuzumab (brand name Herceptin) are known to damage the heart. Herceptin affects the hearts ability to pump blood efficiently which can result in mild to severe heart failure. The most notable symptom of the heart failure is shortness of breath. In severe cases, especially when Herceptin is administered with other chemotherapy drugs, such as Adriamycin, the heart damage can lead to life-threatening congestive heart failure.
Heart Attack
The damage to the heart caused by chemotherapy can, but rarely, lead to a heart attack. Chemotherapy patients are at an increased risk of heart attack, however it is usually brought on due to blood clots instead of heart damage.
Patients with cancer have a higher platelet (the cells in the blood responsible for clotting) count. The increase in platelets means an increased risk of forming blood clots. Once the patient begins chemotherapy, the risk increases even more because as the chemotherapy kills the cancer cells the cells release substances that encourage coagulation of the blood.
The breast cancer chemotherapy medication Tamoxifen is known to increase the risk of blood clots. Blood clots are dangerous because if the clot dislodges from the vein, it can travel to the lungs or the heart where it induces a heart attack.
