Cardiotoxicity in Oncology Treatment: An Introduction
Oncologists and cardiologists have struggled to address late-effect cardiotoxicity in patients with cancer for years, in part because advances in oncologic treatment have extended their lives.
As noted in a 2011 paper in Circulation Research, the 5-year survival for childhood cancers has increased from 30% to 80% in the past 40 years.1.2
Unfortunately, death due to cardiovascular-related causes was 7 times greater in survivors of childhood cancer compared with the expected mortality in expected in an age-matched population.1
Similarly in adults, Dutch researchers found an increased observed-to-expected ratio of 7.1 (95% confidence interval [CI]: 1.9-18.3) for coronary artery disease 10 years after men with testicular cancer were treated with chemotherapy.3
“The SEER [Surveillance, Epidemiology and End Results] database looked at survival rates after cancer and the big number of cancers, most of them survival is improving with time, mostly because of early detection and advancements in therapy,” said Eman A. Hamad, MD.4
Dr Hamad is the medical director of the Mechanical Circulatory Support Program Associate Program and director of the Heart Failure and Transplant Fellowship at Temple University’s Lewis Katz Medical School. “However, these patients that are going on and surviving cancer are getting stuck with heart disease and the effect of the cancer treatment is making their prognosis worse.”
Dr Hamad added that results of a study of more than 2600 patients with cancer published last year in Circulation showed an overall cardiotoxicity incidence of 9%.5
In a study of 3522 adults in Takahata City, Japan, researchers found that patients who had been treated for cancer were at an increased risk for both heart disease (odds ratio [OR]:2.60; 95% CI: 1.06-6.39) and stroke (OR:1.22; 95% CI: 0.37-4.06) compared with the control population. Researchers analyzed data on cancer incidence and death from any cause collected from 2006 to 2008 by the Yamagata Prefectural Cancer Registry, and then followed up with patients in 2011.6
One study of Hodgkin’s lymphoma survivors found a 4- to 6-fold increased standardized incidence ratio of coronary heart disease or heart failure compared with the general population more than 35 years after initial diagnosis. The 40-year cumulative incidence of cardiovascular diseases was 50% (95% CI: 47%-52%), and 51% percent of patients who had cardiovascular disease experienced multiple events.7
The Cardiology Advisor talked to experts in both oncology and cardiology to find out how to treat cancer—often life-saving cancer treatments are associated with increased risk for cardiotoxicity—while protecting survivors from cardiovascular adverse events that can injure or kill years later.
History of Chemotherapy-Induced Cardiotoxicity
Researchers have known about the association between chemotherapy and cardiotoxicity for more than 30 years.8 In a 1991 study of patients treated with anthracycline-based chemotherapy and followed for a median of 7 years, incidence of cardiac dysfunction was 23% and researchers noted a clear dose-response relationship.9
Balaji Tamarappoo, MD, PhD, a staff cardiologist and co-director of the cardio-oncology program at Cleveland Clinic, acknowledges the challenges of balancing the need to treat cancer vs the need to protect against cardiotoxicity. His choice is always for treating the cancer.