Cancer, in itself, is a grave disease that could alter a patient’s life drastically. In the process of treatment, there is a possibility of the medication causing damage to the heart.

Cancer: the word that sends a shudder down our spines. The occurrence of cancer in one's life not only lays an impact on the patient but also the entire family and group of friends. However, consumption of these medicines is inevitable as they can combat cancer and slow the growth of cancer cells in the body. However, what if we told you that these medicines that are meant to treat cancer can, in turn, stimulate heart damage? Yes, it is very much possible.

How do cancer drugs work?

The primary objective of cancer treatment ponders upon the possibility of achieving a cure for the deadly disease; failing which the treatment progresses towards providing pain relief and prolongation of life in the form of palliative care. The former treatment is far more rigorous than the latter. The treatment of cancer depends on the type and the stage. Surgery, radiation, Chemotherapy, immunology, gene therapy, and hormone therapy are the various categories. In all the mentioned cases, cancer drugs are involved to control the growth of cancer cells and to provide strength to the immune system to continue fighting the malignancy. In the case of chemotherapy, the drugs contribute to inhibiting certain stages of cell division, thus causing damage to the cancer cells.

In order to enable the body to fight the diseases, powerful medicines are prescribed to the patients. These medicines are designed to urge the immune system to fight cancer. The medications that cause the immune system to attack the cancer cells are referred to as ‘Immune Checkpoint Inhibitors’. When the body’s natural immune system finds unhealthy and malignant cells, it constantly attacks that cell. The body, in turn, provides additional molecules called immune checkpoints that ensure the safety of the healthy cells. The cancer cells use these immune checkpoints to weaken the immune system, hence making the body more vulnerable to cancer growth. Tumour cells normally cover themselves up with a protein layer stolen from the normal cells. This leads to the immune system leaving these tumour cells in camouflage undetected. The checkpoint inhibitors prevent the camouflage and successfully detect the cancerous cells.  Till date, there are three such checkpoint inhibitors available in the market: ipilimumab (brand name Yervoy), nivolumab (Opdivo), pembrolizumab (Keytruda) and atezolizumab (Tecentriq).

Similar to checkpoint inhibitors, chemotherapy drugs such as anthracyclines and relatively newer medicines like trastuzumab (Herceptin) and pertuzumab (Perjeta) can also cause the heart to weaken and function improperly. Chemotherapy treatment is provided after having properly studied heart function and prior heart diseases and anomalies. In the case of radiation therapy, if the radiation areas are close to the heart, it could lead to problems such as heart attack, coronary heart disease, and cardiac myopathy, to name a few.

How do checkpoint inhibitors affect the heart?

The function of the checkpoint inhibitors revolves around the immune system. In extreme cases, these life-saving drugs could provoke the immune system into attacking the heart. It leads to the weakening of the heart muscles and causes disruptions in the heart rhythm.  The number of cases is not many but for those whose heart caused trouble due to these cancer drugs, the effects were severe and it has even lead to tragic deaths. Due to the occurrence of these deaths and heart problems due to prescribed cancer medication, hospitals have been extra vigilance on the type of drugs a patient should take, especially if they are consuming more than one drug. They take into consideration results of cardiac testing sessions that ensure that a certain drug is completely safe for the patient’s heart. In addition, heart damage only occurs in patients who consume more than one such drug. It is, of course, a complication that needs to be addressed. Fortunately, deaths and heart damage due to cancer drugs is very rare. A mere 1% of cancer patients have been prone to heart trouble on taking more than one type of drug.

While these cancer-fighting drugs function with the positive intention of survival, they could also cause other health complications related to the heart. Cancer treatment does have side-effects. But, drug prescriptions should be prudent. Patients should undergo several tests to understand what type of treatment and drugs are most suitable for them. The skill involves being able to work around the side-effects of these cancer treatments to ensure optimum health and cancer-free survival to patients.