The Cardiology-Cancer Connection
Cancer is the second leading cause of death in the United States after cardiovascular disease; the survival rate of all types of cancer has improved in the last 25 years from 50 percent to 68 percent as a result of more successful anticancer therapies by oncologists. There are currently over 12 million cancer survivors. This, however, comes with a price, as cardiac toxicity stemming from oncology treatments is a common adverse effect. It has resulted in more interaction between cardiologists and oncologists.
Adverse effects include direct toxicity to the cardiac muscle cells (myocytes) from chemotherapy, resulting in defects in contractility of the heart and ultimately leading to congestive heart failure of varying degrees. Another source of toxicity is radiation therapy, which can cause valvular problems and pericarditis. Other drugs used in cancer treatment can also cause blood pressure and lipid abnormalities. There are situations in which more than one agent is used, therefore increasing the possibility of cardiac toxicity.
Two Types of Cardiac Toxicity
One type of cardiac toxicity is caused by direct action on the heart's left ventricle, causing heart failure as a final result. This is a direct effect from drugs of the anthracycline type, like doxorubicin, and its effect is nonreversible and generally dose-related.
A mediated cardiac toxicity is caused by monoclonal antibodies, such as protein kinase inhibitors (KI) like Herceptin. This adverse effect is reversible and not dose-dependent; outcomes are more favorable than in the other type.
An integration between clinical oncology and cardiology is essential to detect early signs of toxicity. This collaboration involves cardiac testing, such as echocardiography or nuclear cardiology, which facilitates the decision to delay or modify treatment as needed. The use of cardiac protecting agents (i.e., beta blockers, ACE inhibitors or ARBs, or diuretics) becomes necessary as soon as any cardiac dysfunction is detected. These therapies are also useful once heart abnormalities are present.
Direct communication between oncologists and cardiologists is vital in reaching a common goal: a cancer-free, heart-healthy patient. Be sure to discuss cardiac toxicity with your physician.
Holy Cross Hospital in Fort Lauderdale, Florida is one of the few facilities in the nation dedicated to minimizing cardiac toxicity during cancer treatment and cardiovascular risks during cancer survival. Click to learn more about Holy Cross' Cardio-Oncology Clinic.