Due to the increased incidence of cancer and the longer survival of patients, the prevention and treatment of cardiovascular diseases in this population have been gaining prominence. Cardiotoxicity is one of the most significant complications of cancer treatment, responsible for considerable morbidity and mortality, i.e., not only increasing the risk of death but also causing important sequelae for the patient.
Currently, the early identification of cardiovascular risk, the implementation of strategies for risk reduction, the correct diagnosis of the cardiovascular problem, and the institution of effective therapy are essential for the adequate care of the cancer patient. This set of measures aims to reduce the mortality risk and improve the patient’s quality of life, without interfering, if possible, with the specific cancer treatment.
What is cardiotoxicity and main symptoms⁵
Cardiotoxicity is the damage caused to the heart by cancer treatment, and can occur as a result of an alteration or damage to the heart muscle, or to the electrical system of the heart, for example. The most worrisome injury is heart failure, which occurs when the organ becomes weaker and is not as efficient at pumping, which compromises blood circulation. There are other effects of cancer treatment that affect the patient such as acute coronary insufficiency (heart attack), hypertension, arrhythmias, and thromboembolic events.
If the treatment regimen causes thrombosis, which can be in the leg or even pulmonary embolism, symptoms include:
- Rapid breathing, shortness of breath, chest pain and palpitations, in the lung;
- Swelling in one of the legs and redness, increased temperature in the leg, and pain to the touch.
The symptoms of heart failure, which occurs when the heart loses strength, are:
- Swelling in the legs in a symmetrical fashion;
- Shortness of breath during activities that used to be performed normally;
- Shortness of breath when lying down, which improves when sitting up;
- Easy fatigue.
Treatments that can cause cardiotoxicity⁵
Chemotherapy – it is not the only treatment that can lead to heart problems, although it is the most common among the therapeutic approaches adopted in oncology. Toxicity to the cardiovascular system is variable and depends on the therapeutic scheme used. Certain strategies with chemotherapy drugs are directly toxic to the organ, causing it to lose strength, leading to heart failure. Other protocols can lead to increased blood pressure, or a higher incidence of thrombosis or change in coronary circulation – this can cause myocardial infarction or ischemia, or cause palpitation and arrhythmias.
Radiotherapy – when performed in the region of the thorax, it can cause an involvement of the pericardium, which is a membrane that surrounds the heart. As a result, it can become thicker and harder. Besides increasing the risk of atherosclerosis (fatty plaque in the vessels), which in the long run. It can lead to heart attack.
Immunotherapy – drugs that stimulate the body’s defense system to fight cancer – can lead to myocarditis, an acute inflammation in the heart, and it is possible that monoclonal antibodies can cause heart damage.
The importance of early risk assessment ²,¹
To prevent problems with the heart, cancer patients should ideally have a complete cardiological evaluation before they start chemotherapy or radiation therapy. In this evaluation, in addition to clinical tests, the doctor may order specific blood tests to evaluate cardiovascular health markers such as Troponins and BNP (Natriuretic Peptide). In addition, imaging tests, such as an echocardiogram, may also be ordered for a structural evaluation of the heart.
Electrocardiogram – routinely performed in the evaluation of the patient with risk factors for cardiotoxicity. The detection of ventricular and supraventricular arrhythmias, such as atrial fibrillation, alerts the clinician to the presence of structural heart damage.
Cardiospecific biomarkers – This is a useful tool in the early identification of cardiac injury from chemotherapy. Blood tests can detect these cardiac specific biomarkers suggesting potential development of a heart problem.
Imaging Methods – Prior to the initiation of cardiotoxic chemotherapy, evaluation and quantification of ventricular function by imaging methods are necessary. This should be measured by Doppler echocardiography. The physician can discuss with the patient the possible chemotherapy regimens with less cardiovascular risk. The echocardiogram has been the most used option because of its low cost, easy access, and non-invasive character.
Healthy routine helps in prevention ²,¹
It is important that even after a cancer diagnosis, the patient whenever possible maintain a routine of physical activity and healthy eating. The benefits of this care are well established in improving quality of life and significantly reducing the risk of developing cardiovascular and metabolic diseases. A sedentary lifestyle is associated with a significantly increased risk of obesity, metabolic syndrome, and coronary events.
Current evidence suggests that increased physical activity after cancer diagnosis may reduce the risk of recurrence and mortality. Cancer and its treatment are associated with a number of systemic metabolic changes that can significantly compromise a patient’s quality of life and life expectancy even after cure.
Which physicians should provide guidance on cardio-oncology
Guidance about the risks of chemotherapeutic agents causing heart problems should be passed on to the patient initially by his or her oncologist. The evaluation and, if necessary, the beginning of prevention schemes for cardiac problems potentiated by the treatment should be done by a cardio-oncologist.
Nowadays, there are specific residencies in cardio-oncology, which are trained cardiologists but specialists in oncologic patients. Large centers specializing in oncology treatment have these professionals on the team accompanying the patient.