INTRODUCTION AND EPIDEMIOLOGY
With the advent of more effective cancer treatments and the increasing likelihood of an earlier cancer diagnosis, patients with many forms of cancer can expect to either be cured of their disease or have their disease stabilized by maintenance therapy. Although the overall rate of cancer incidence has declined since the early 2000s,1 cancers necessitating aggressive chemotherapy, including melanoma, non-Hodgkin lymphoma, leukemia, and those of the pancreas and esophagus have been on the rise. Accompanying this trend, the length of cancer survival has increased for all cancers combined. The 5-year survival rate for all cancers combined improved from 66.7% in 2003 to 68% in 2009.1 This implies that cancer survivors now live longer, allowing the manifestation of potential cardiac side effects of chemotherapeutic agents as well as the age-related increase in the risk of cardiovascular disease.
For individuals free of cardiovascular disease at 50 years of age, more than half of men and nearly 40% of women will develop cardiovascular disease during their remaining lifetime. Other than the extended survival of cancer patients and the aging population, there has been an increase in the recognition of chemotherapy-induced cardiotoxicity, adding to the linkage between patients with cancer and their risk for cardiovascular diseases. In addition, some patients with cancer may be at a higher risk for cardiovascular complications as compared with the general population.2 Multiple classes of potentially cardiotoxic anticancer agents are currently being developed. Indeed, the combination of increased use of chemotherapy, overall increased survival, and development of newer agents have led to the emergence of chemotherapy-induced cardiotoxicity as a growing public health issue.
Moreover, one of the most significant late toxicities in survivors of childhood cancers is late-onset cardiotoxicity, largely as a result of anthracycline and chest-directed radiation exposure. Survivors also have an increased prevalence of traditional cardiovascular risk factors as they age, which potentiates the risk for major adverse cardiac events. Prevention of cardiotoxicity is essential in this population. Minimizing anthracycline dose exposure in pediatric cancer patients is a primary method of cardioprotection. Dexrazoxane and enalapril have also been studied as primary (pre-exposure) and secondary (post-exposure) cardioprotectant agents, respectively. Additionally, the Children’s Oncology Group has published exposure-driven, risk-based screening guidelines for long-term follow-up, which may be a cost-effective way to identify subclinical cardiac disease before progression to clinical presentation. Ongoing research is needed to determine the most effective diagnostic modality for screening (eg, echocardiography) and the most effective intervention strategies to improve long-term outcomes.3
Cardiologists dedicated to the care of patients with chemotherapy-induced cardiotoxicity and with concomitant cardiovascular problems in cancer patients are a part of an emerging subspeciality called “Cardio-Oncology” or “Onco-Cardiology.” Many cancer centers and tertiary care hospitals in the United States are now establishing dedicated Cardio-Oncology clinics where cardiovascular specialists play a dedicated role in managing heart disease in cancer patients. The reason for this evolving need for specialized cardiac care in ...